This paper introduces taxation system, taxation rate design, fee deduction, calculation method for income tax, estimated tax and so on of the personal income tax of Belgium. Based on the reasonable taxation methods of Belgium, this paper makes suggestions for completing China's personal income tax system such as changing present classified taxation system into comprehensive classified taxation system, reducing tax rate level, decreasing the highest marginal tax rate, considering the situation of the individual and family when fees are deducted, adjusting taxation income with the changing of inflation, accelerating credit system construction, completing personal income tax system.