An Empirical Study On The Income Redistribution Effect Of China’s 2018 Personal Income Tax Reform

China’s economy has experienced many years of rapid development,the level of residents’ income has increased significantly,but the gap between the rich and the poor has become increasingly prominent.As an important tool to adjust the gap between the rich and the poor in the field of income redistribution,individual income tax reform has been widely concerned by the society.In 2018,the reform of individual income tax moved from categorization to comprehensive and categorization.At the same time,the decision was made to increase the amount of deductions for expenses and implement special additional deductions in general.This study uses theoretical and empirical analysis to quantify the income redistribution effect of the 2018 individual income tax reform,and further puts forward the tax optimization design scheme,and calculates and compares the effect of each simulation scheme.The research findings are as follows: First,the reform of individual income tax in 2018 significantly improved the progressivity of individual income tax,but led to a substantial reduction in the average tax rate and RE index,which weakened the adjustment effect of income distribution to some extent.However,with the continuous growth of residents’ income level,the adjustment ability will be enhanced continuously.Second,the specific analysis of individual measures of reform,comprehensive levy is conducive to the improvement of the redistribution effect,the increase of the expense deduction and the renewal of tax rate are due to the significant reduction of the average effective tax rate,thus weakening the redistribution effect,and they have a great impact on the income redistribution effect,the comprehensive levy has a small positive impact.Thirdly,according to the calculation results of the simulation scheme,the adjustment of tax rate structure has a greater contribution to the promotion of redistribution effect,followed by the setting of the optimal expense deduction and the expansion of the comprehensive collection scope.Furthermore,the thesis puts forward specific plans for future reform based on the experience of other countries: first,optimize the design of tax system from three aspects: expanding the scope of comprehensive levy,improving the system of expense deduction and optimizing the tax rate levels;Second,we will improve the supporting collection and management system with information as its core to support the effective implementation of the individual income tax system.