>This paper combines population censuses of 1990 and 2000 and data from other sources to analyze the interrelationship between regional income divergence and population mobility. During the 1990s，relative incomes between coastal and inland regions in China increased substantially. Much of this divergence is related to the urban-rural divide and accounted for by diverging performance within rural areas between coastal and inland regions and by differential rates of labor transfer from rural to urban sectors. In the same period，the rate of inter-provincial population migration more than doubled. This is consistent with increased responsiveness of migration to regional income differential. The elasticity of migration to income gap was 0.197 in 1985～1990，rising to 0.595 in 1995～2000. However，the intensified migration activities in the 1990s have not been sufficient to reduce regional income disparity. This may be due to two major factors. One is continued external pressures pushing up the regional income disparity. The second is continued restraints on migration.