Both the theoretical and empirical analysis of the influence of population size’s changes show that the slow growth rate of population size results in the changes of economic growth pattern,thus it has put higher demands for migrant workers;cultural quality.However,the upgrading of migrant workers’ cultural quality does not correspond with the demands of the economic development.The joint efforts between economic scale and the cultural quality lead to the migrant workers’ return,the aged structure,the upgraded rural aged level,the average migrant workers’ age and their marriage ratio also lead to the migrant workers’ return.In order to keep the appropriate scale of migrant workers’ return,the working mechanism of the influence of the population size’s changes on the migrant workers’ return demands that the population management should maintain the existing birth policy,improve the cultural quality of rural population,increase and perfect facilities for the elderly in rural areas.