Under normal circumstances, when taxpayers use up invoices and hand them in for cancellation, the tax authorities will check them; Under special circumstances, if someone reports that the invoice is illegal, it is necessary to check it; In addition, after the tax authorities collect the invoice information of the ticketing unit by themselves, they compare the information through the invoice comparison system (comparing the data of invoices and stubs) to check the use of invoices. There is no fixed time for the above inspection, just check and spot check at any time. Tax inspection is a way for tax authorities to conduct large-scale tax inspection on taxpayers who think there are problems. According to the tax credit rating of Agricultural Bank of China, the tax authorities generally inspect Class A enterprises once every three years, Class B enterprises once every two years and Class C enterprises once a year. In addition to reporting, always check.