Assuming you mean income tax. For the most part in varies from province to province. In some provinces tax is not paid at all. This is not true as far as the government is concerned but true to my experience in China.

Officially it based on how much a person earns. You can see the deduction in the following table:

Taxable items and calculation of Individual Income Tax payable
a. Wages and salaries
Wages and salaries are taxed on the basis of the balance of taxpayer' s monthly wages and salaries after lump-sum deduction of expenses (3500 yuan for mainland citizens, 4800 for foreigners)

Grade Monthly Taxable Income Tax Rate (%) Quick Deduction
1 Income of 4,500 yuan or less 3 0
2 That part of income in excess of 4,500 to 7,500 yuan 10 105
3 That part of income in excess of 7,500 to 12,000 yuan 20 555
4 That part of income in excess of 12,000 to 38,000 yuan 25 1005
5 That part of income in excess of 38,000 to 58,000 yuan 30 2755
6 That part of income in excess of 58,000 to 83,000 yuan 35 5505
7 That part of income in excess of 83,000 yuan 45 13505

The formula for computing the amount of tax payable is:
Monthly taxable income = Monthly aggregate wages/salaries - 800 yuan
Monthly amount of tax payable = Monthly taxable income ×Applicable rate - Quick deduction
The taxpayers who have no domiciles in China but earn wages and salaries from China or who have domiciles in China and earn wages and salaries from outside China may enjoy additional expense deductions (currently 4000 yuan per month) in addition to the regular monthly deduction of 800 yuan in computing the taxable income.