In this study，we construct a multidimensional framework for analyzing marital stability among floating population，generate hypotheses，and test them based on a large sample survey of 157535 migrants’households in 106 cities in China．The prevalent divorce rates among floating population are of clear patterns by age，education and urban/rural type，with higher rates for older，more educated and urban-registered residents．By province，the divorce rate of flow-in migrants is similar to that of flow-out migrants，reflecting regionalized cultural effects on marriage．The risk of divorce is enhanced in the migration process during which the quality of marriage declines，contacts for the substitution increase，and search costs for marriage reduce．Regression results show that the odds of being divorced are greater for solely moved husbands ( than wives) and those who migrated for a longer period and over a shorter distance．

Modernization theory predicts loosening family ties and the gradual decline of family supports for the elderly.In a transitional economy,we argue that the rapidly growing income for adult children helps to maintain family supports for the elderly at a high level.Data from 2005 China’s 1% population survey shows that half of elderly people in towns or rural areas relied on family supports as the main source for living.The odds-ratio from Logistic regression shows that family supports were far greater for females than males and far greater for rural than for urban residents.Labor migration by a rural household member greatly enhanced the odds of family supports for the elderly in rural areas.In the cities,we found that the odds of family support were the highest in the well-developed regions along the coast.As the population is rapidly aging,more government efforts are needed to expand socialized supports for the elderly,especially to the weakest.

 Based on the 1% Population Survey of China in 2005,we examine the size and distribution of floating population in the context of regional competition.We found that the size of short-term labor migrants is not negligible,amounted to nearly 17 million,which accounted for 2% to 3% of the total population in the coastal regions.Totally 150 million migrants left their place of registration,mainly inter-provincial in the coastal regions and largely intra-provincial in the interior.Among seventy million interprovincial ones,three-fourth were originated from nine sending provinces in the interior and about three-fourth headed to Guangdong(34.2%),Yangzi-River-Delta Region(28.5%)and the Regions surrounding the Bohai Bay(13%).The destination choice between Guangdong and YRD region is mainly affected by distances to the two regions,being highly concentrated for a neighboring province but spread for distant ones.The above results reflect a strong magnet force of the growth poles on people in the interior as well as increasing regional competition for labor,which helps to explain the labor shortage in despite of massive labor migrations.