内容提要：自上个世纪90年代以来，我国的迁徙政策受到了严峻挑战，既不能挡住求生存的农民进城，也没有将贫困的农民工排出城市，甚至使一部分人比农村时更贫困，使得城市的贫困问题更加尖锐。我们建立了一个异质的农村人口向城市迁徙的模型来研究这个挑战。这个模型假设绝大部分进城的农民只能成为城市的流动人口，在竞争的劳动市场上搜寻工作；城乡差别很大，农民务农的收入与在城市打工的收入是异质的。我们证明了迁徙政策对农民的限制越大，他们向城市迁徙的愿望越强烈；歧视性迁徙政策甚至会使一些来自农村的流动人口比在农村时更贫困但不愿离开城市，沦为城市的贫困人口。
Migration Policies, Urban Poverties and Rural-urban Migrations
Since 1990s, it has been a puzzle that migration policies not only do not discourage peasants from making a living in city, but also do not drive poor peasants out of city, and even make some of them poorer in city than in countryside, and aggravate urban poverties. We develop a heterogeneous rural-urban migration model to account for this puzzle. The model assumes that most of immigrants from countryside can only become floating people in cities, and search jobs in competitive labor force markets; the Chinese rural-urban gap is very large, farming income is different from that earned in cities. We show that the more severe migration policies, the stronger peasant’s desires for rural-urban migrations; discriminating migration policies even make some floating people from countryside poorer in cities than in countryside but have no desire for leaving cities and sink to be poor urban people.
Key words: market economic institutions migration policies urban poverties
