Ad valorem tax is linked to commodity prices year-on-year, and its tariff revenue and tariff burden change with the change of commodity prices, which is conducive to the financial and protective role of tariffs.

For goods with uniform tax items, it is unreasonable to calculate tax at the same tax rate in the case of great differences in specifications, quality and price; In the case of price changes, taxes cannot increase or decrease accordingly.

Therefore, most international trade is calculated by ad valorem tax.