Abstract: Does the individual income tax have the function of regulating the income gap as the important policy tool for regulating the income distribution in China? On this proposition the existing literature lack of comprehensive practical demonstration. This paper chooses the average tax rate progressivity and pre-tax and after-tax Gini coefficient as measure index, using the survey data of urban residents, to demonstrate the income distribution effect of the individual income tax from the structure and overall view. Through empirical analysis the author find three truths. First, the average tax rate of the individual income is progressive among the different income groups. Second, urban residents Gini coefficient of after-tax individual income is less than the pre-tax Gini coefficient, thus the individual income tax narrows the income gap. Third, the income distribution Effect of the individual income tax is different in different periods.