In China the high level of intercity mobility of migrant workers is not conducive to the sustainable development of urbanization． Based on a survey of migrant workers in six cities in Eastern China，this research analyzes the features of spatial mobility and group differentiation of migrant workers，and investigates the individual －level factors determining spatial mobility level as well as factors representing the relations between migrant workers and socioeconomic environment． Age，educational attainment and number of years since out －migration from rural home are significant individual －level determinantsof spatial mobility．With respect to the individual －environment relations，influential factors include family accompanying status，income，industry urban pension insurance participation，and social relationship with local communities． Higher level of urban integration is associated with lower spatial mobility， longer duration of stay in the city，and more stable work and life．