Abstract: Since quality and efficiency are equally considered, the change of optimal nonlinear income tax rate is the interactive result. Based on formula of optimal marginal tax rate structure, numerical simulations results and empirical evidence, mechanism of social welfare function, skill distribution, utility function and the level of labor supply elasticity on the optimal marginal tax rates are deeply analyzed with a completely research review. The results indicate that, it is not true that a higher marginal tax rate is caused by a highly fair social welfare function, lower labor supply elasticity, skills of Pareto distribution and the quasi-linear preference, on the other hand, different optimal income tax structure is needed for each country since the optimal income tax theory is built on many simplifying assumption.

摘要： 最优所得税同时考虑公平与效率，税率结构的变化某种程度上都源自两者的权衡。根据最优税率结构的求解公式、模拟结果及经验证据，围绕社会福利函数、技能分布、效用函数以及劳动供给弹性等，分析其对最优税率的影响。一方面，认为更平等的社会福利函数、更小的劳动供给弹性、技能的帕累托分布和效用的拟线性偏好会产生更高的边际税率，这一普遍观点并不完全成立。另一方面，最优所得税是建立在严格的假设条件基础上的，因而各国要根据自身情况构建最优税制。