中文摘要：

根据人口普查数据，本文利用DFL分解和综合技能模型两种半参数方法讨论了农民工与城镇职工小时工资收入差距的形成原因。结果表明，假设农民工具有与城镇职工相同的回报系数（技能价格），其反事实平均收入水平不仅不会上升，反而略有下降；农民工内部的收入差距将有所上升。综合技能模型的结果表明农民工的技能回报具有非线性形式，高技能者的回报率高于低技能者。该模型的结果同时说明了测量误差问题的重要性。

英文摘要：

Using 2005 census data, we investigate the income differential be- tween rural migrants and urban residents. The decomposition results from two complementary semi- parametric approaches （DFL and Single Index Model） indi- cate that difference in characteristics is the main reason that rural migrants earn less. If migrants were paid as the same as urban residents, their average income will decrease slightly, and their within- group inequality will increase.