The collection of tax data is very important to solve the problem of e-commerce tax collection and management in the era of big data, and the corresponding taxpayers must bear corresponding obligations in the supply of tax-related information. In this regard, China should make clear the nature, time limit and place of tax payers and tax recipients according to the relevant information flow, cash flow and goods flow, and reduce tax evasion and deepen the electronic tax inspection by improving the tax registration of e-commerce, standardizing the issuance of electronic invoices. Especially in the field of source supervision of information, we must do a good job in tax registration and encourage taxpayers to declare relevant tax-related information independently.

First of all, China should constantly establish and improve relevant laws, clarify the obligation of e-commerce service providers to assist tax authorities in handling tax-related information in future laws and regulations such as the E-commerce Law and the Measures for the Administration of E-commerce Taxation, provide clear rules and guidelines for them to assist tax authorities in managing tax-related information, and require taxpayers to go to the competent tax authorities for tax registration of e-commerce after handling online transactions, and obtain a special tax registration number. At the same time, the tax authorities should strictly examine the online transactions declared by taxpayers, register them one by one, and supervise and govern taxpayers through tax registration. Secondly, the publicity of tax registration should be done well, and the original data should be made public as much as possible, so as to facilitate the public to inquire relevant information online. Take Guangdong Provincial Local Taxation Bureau as an example. At present, the local taxation bureau of Guangdong Province is gradually promoting the construction of a transparent tax bureau by relying on the big data platform. The public can query the total tax revenue of Guangdong Province, distinguish tax revenue by region, and also query data such as corporate tax payment, personal income tax, social security fee, tax arrears announcement, tax credit rating, electronic invoice inspection and taxpayer status. [Visible, constantly promoting the "transparency" of tax information is an important way to improve taxpayer compliance. In terms of specific publicity methods, we can adopt such an approach: for enterprises that build their own websites to carry out e-commerce activities, they can be required to register their taxes on the website for permanent display; For enterprises that use third-party special e-commerce websites to carry out e-commerce activities, they should be required to display tax registration information at the merchant introduction office, promote personal e-commerce operation in real-name registration system, and improve the tax registration system under the conditions of e-commerce. Finally, in the era of big data, we should continue to strengthen the institutional incentives for taxpayers to declare independently. At present, the system of taxpayers' self-declaration in China is still not perfect. According to the provisions of the Measures for Self-declaration of Individual Income Tax (Trial), only taxpayers with an annual income of120,000 or more apply the self-declaration system, and other taxpayers still rely on the "inspection" of the tax authorities to collect taxes, which brings abnormally high tax collection and management costs. Therefore, China should constantly promote the improvement of tax collection and management mode supported by "administrative coercive force" to "taxpayers declare and obey themselves", encourage taxpayers to declare tax information by promoting the reform of tax legislation system, and finally urge taxpayers to pay taxes consciously and honestly. [ 14]

2. Real-time tracking: the establishment of e-commerce tax collection and data exchange system.

E-commerce usually changes the transaction form and content of traditional commerce, such as changing tangible products into intangible products, changing text services into digital information services, etc. Therefore, compared with traditional transactions, e-commerce transactions will be unable to monitor specific transaction information due to the lack of "intermediate links", which will lead to the narrowing or even disappearance of the tax base. Coupled with the electronicization of online transactions and the emergence of online banks, it is difficult for tax authorities to clarify whether they should be taxed or exempted when finding out the supply channels and sources of payment, which also brings unfairness to taxpayers' tax burden in e-commerce and traditional commerce. In view of this, we should start with building a "middle bridge", promoting the legal "levy" system of e-commerce taxation, and constantly strengthening the information sharing and exchange system of tax data, and constantly strengthening the collection and management of e-commerce taxation.

First, we should gradually establish a legal "levy" system in the field of e-commerce. At present, one of the important reasons why China's e-commerce taxation is difficult is that the tax source is difficult to monitor. Taking C2C mode as an example, each online trading platform will launch its own e-commerce payment information as a third party to manage payment settlement, so as to ensure the convenience and security of electronic payment. In this mode, the third-party payment platform in the "middle position" is easy to control the business scale, account information and transaction amount of personal online stores. Therefore, we can establish a legal mechanism for online payment platforms (Alipay, Tenpay, Express Payment and online banking) to collect and collect taxes according to the characteristics of online payment third parties, and the tax authorities will entrust the relevant online payment platforms to collect the taxes of relevant suppliers, especially those without tax registration, in order to solve the problem of tax collection. [15] In terms of specific operation, we can take Taobao as an example, and standardize the process of third-party payment of e-commerce tax as follows: the buyer pays Alipay after purchasing the goods, and directly withholds the tax in Alipay after confirming the buyer's receipt.

Second, we should gradually promote the use of electronic invoices in online transactions. E-commerce transactions have not only updated the transaction mode, but also impacted the traditional tax collection and management mode in China. Under this background, e-commerce transactions based on information need to be managed through the new invoice style of "electronic invoice". Electronic invoice is the new product of the change of invoice form and service management mode in the information age. It is the electronic record information of storage information system and adopts a brand-new paperless invoice form. Its launch broke the "hidden rule" that there is no invoice in online transactions, which not only laid the foundation for the fairness and security of e-commerce transactions, but also filled the gap in invoice management and tax management. With the help of electronic invoices, tax authorities can manage the circulation, storage, inspection and comparison of invoices in an all-round way, and then they can control the transaction information of related e-commerce in real time, and give play to the tax agglomeration effect of e-commerce. Therefore, China should promote the use of electronic invoices in e-commerce transactions under the background of vigorously piloting electronic invoices at present. Third, efforts should be made to promote the construction of information sharing mechanism in the era of big data. With the development of technology and informatization, information sharing has become an inevitable trend and choice in the era of big data. As an important part of big data, tax data must also strengthen the construction of "information management tax" and promote tax collection and management of e-commerce. Just as e-commerce needs a third-party payment platform, tax collection and management also needs a third-party auxiliary platform. In China, the auxiliary platform for tax collection and management is mainly "China Tax Collection and Management Information System (CTAIS)". However, although the system has been successfully launched in most provinces and cities in China, and the tax revenue involved accounts for 70% of the whole country, many existing data flows are still superficial, and the advantages of the system in e-commerce tax collection and management cannot be brought into play. In view of this, in the era of big data, tax authorities must strengthen information construction on the premise of ensuring data availability, realize data connection with banks, customs and online business users as soon as possible, effectively monitor the data of production and trading activities of enterprises, and promote the "networking" of information verification and monitoring. In the field of cross-border electronic commerce, we should also fully connect with the Internet as soon as possible, reach an agreement on tax exchange and tax compliance, and prevent tax loss in the field of e-commerce and crack down on tax evasion through online cooperation with tax bureaus of various countries.

3. Follow-up supervision: establish a risk assessment and management mechanism for e-commerce tax data.

In order to prevent "information bias" and enhance the certainty of tax data, China should also actively carry out the analysis and comparison of e-commerce data on the basis of taxpayers' independent declaration and statutory collection, and do a good job in risk assessment and management of tax data. First of all, the tax authorities should establish an effective connection between the network economy and the real economy, bring e-commerce enterprises into the early warning and evaluation system of the provincial bureau, regularly publish risk early warning information, and bring e-commerce into the normal tax source monitoring range to further reduce tax loss. Secondly, as the competent authority of information management, tax authorities should abide by the "due process principle" and adopt scientific and reasonable management procedures and methods in the process of information processing to avoid information and related data being tampered with and distorted in the process of management. In this regard, in order to make it convenient for tax authorities to use relevant tax-related information and for stakeholders to inquire about relevant information, encryption settings can be introduced into the management of big data to provide technical support for tax authorities and stakeholders in key or decryption, so as to prevent information from being illegally inquired, tampered with or deleted. Finally, legal responsibility is the guarantee for the implementation of the system. Under the platform of big data, if the tax authorities violate the confidentiality obligations of relevant tax-related information management and illegally disclose the information of taxpayers in the field of e-commerce, they should bear relevant administrative responsibilities and make reasonable administrative compensation for the losses caused by taxpayers; If a third party other than the tax authorities illegally discloses and infringes on the taxpayer's tax-related information, it should bear the corresponding civil tort liability to make up for the damage caused to the taxpayer's legitimate rights and interests.