经典经济学认为,城乡移民(农民工进城)减少了收入不平等,但迄今并无严格的分析。本文从理论上讨论农民工进城对于以基尼系数衡量的收入不平等的影响,关键假设是把农民工看成一个独立的群体加以考虑。研究表明,农民工进城并不总是减少收入不平等;特别是在城乡移民早期,很可能增加收入不平等。本文还讨论了农民工进城以及户籍改革对于城镇内部、农村内部和城乡之间收入不平等的影响。 Classical economics believes that urban-rural immigrants (migrant workers into the city) to reduce income inequality, but so far there is no rigorous analysis. This paper theoretically discusses the effect of migrant workers entering the city on income inequality as measured by the Gini coefficient. The key assumption is to consider migrant workers as an independent group. Research shows that migrant workers entering cities do not always reduce their income inequality; especially in the early stages of urban-rural migration, they are likely to increase their income inequality. The article also discusses the impact of migrant workers entering cities and household registration reforms on income inequality within and between rural areas and between urban and rural areas.