According to the regulations of the General Administration of Customs of China, it is the first time to use the cross-border e-commerce platform to purchase a single item of 3,000 yuan, and the tariff rate of retail import in cross-border electronic commerce is 0%. Tax declaration refers to the legal act of taxpayers submitting written reports to tax authorities on tax matters in accordance with the time limit and contents stipulated in the tax law. It is the main basis for taxpayers to fulfill their tax obligations and bear legal responsibilities, the main source of tax management information of tax authorities and an important system of tax management.