At present, tax revenue accounts for more than 95% of fiscal revenue. As a form of distribution, taxation, compared with other forms of distribution, is compulsory (meaning that taxation relies on the political power of the state, and no unit or individual can violate it through the promulgation and implementation of laws, otherwise the responsibility will be investigated), free (meaning that after the state levies taxes, the tax is owned by the state, and it does not need to be repaid, nor does it need to pay any price to taxpayers), fixed (meaning that the object of taxation and the unified proportion or amount are stipulated in the form of law before taxation, and Any other distribution form does not have these three characteristics at the same time, so it is impossible for other income to account for the largest proportion.