关键词: 关键词：收入分布, 基尼系数；洛仑兹曲线；随机占优

Abstract: Abstract: Although the empirical researches about the Gini coefficient are extraordinarily plentiful, the formal theoretical deduction of the Gini coefficient is usually omitted. This paper attempts to formally explore the theoretical definition and properties of the Gini coefficient under continuous income distribution in order to clear up some misunderstanding about the Gini coefficient. The optimal value of Gini coefficient will necessarily be concerned with the value judgment of the social welfare and thus cannot be obtained from the definition of Gini coefficient itself. In addition, given the specific income distribution function, the calculation of the Gini coefficient can be realized by the parameter estimation about the income distribution function. A simple rule for generating income distribution function and calculating the Gini coefficient is proposed in the final section.

Key words: Key words: Income Distribution, Gini Coefficient, Lorenz Curve, Stochastic Dominance