How China IIT works for foreign residents
Foreign nationals who are China tax residents are subject to IIT on their income. China uses a 183-day presence rule to determine tax residency: if you spend 183 or more days in mainland China during a calendar year, you are a China tax resident for that year and your China-sourced income is taxable in China.
The scope of income subject to Chinese IIT expands with the length of your China residence. The six-year rule determines when global income (including income from outside China) becomes subject to Chinese IIT. For most recently-arrived expatriates, only China-sourced income is taxed here.
For employed expatriates, IIT is typically withheld at source by the employer's Chinese payroll entity. The employer calculates the applicable bracket, withholds the tax monthly, and remits it to the State Taxation Administration. The annual reconciliation (filed typically in March–June for the prior year through the individual tax app) adjusts for any over- or under-withholding.