the base on which the tax payable is calculated. Including physical quantity and value quantity. The former, such as the number of acres of land, the number of houses, the number of vehicles and tonnage, etc. The latter, such as the amount of sales income of commodities and the income tax of individuals and enterprises. The tax base is one of the tax bases. When the tax rate remains unchanged, expanding the tax base will increase the tax amount, while narrowing the tax base will reduce the tax amount. The tax base restricts the specific form and standard of tax rate. When the tax base is physical quantity, the tax rate is mostly fixed tax rate. When the tax base is value quantity, the tax rate is mostly proportional tax rate or progressive tax rate in percentage form. If a progressive tax rate is implemented, the tax rate will increase with the increase of the tax base. The tax base is related to the number of tax objects, but there are also differences. The connection between the two is that in many cases, the tax base is directly a profit expression of the number of taxable objects. For example, when taxing goods, the tax base is the number, tonnage, degree or sales income of goods, and when taxing income, the tax base is the income. The difference between the two is that in some cases, the tax base is only a part of the tax object, not all of it. For example, in the case of enterprise income tax, the tax target amount is the total income, and the tax base is the balance after some deductions. In the case of individual income tax, the tax base is the part of all income that exceeds the exemption amount.

Tax source refers to the economic source of tax collection. The object of tax distribution is national income, and it is mainly the surplus products. Broadly speaking, the tax source is, in the final analysis, the national income created by workers in the material production sector. That is to say, tax revenue comes from the economy. Without the development of the economy, tax revenue will become passive water and a tree without roots. But in a narrow sense, tax sources refer to the tax targets determined by various taxes.