Abstract: Based on the data of China Migrants Dynamic Survey in 2017 and the matching data of 234 prefecture level cities, this paper systematically investigates the impact of urban workers’ medical insurance on the labor supply of migrant workers. The findings show that: (1) to participate in urban workers’ medical insurance will reduce the labor supply time of migrant workers and improve labor efficiency, showing an income effect and a positive labor supply effect. (2) there is obvious differentiation of labor supply effect in urban workers’ medical insurance. For migrant workers who participate inthe way of “unit+individual”, there is mainly an income effect; while for migrant workers who participate in the way of flexible employment status, there is a payment constraint; the urban workers’ medical insurance has a stronger effect on relieving the excessive work of the older generation of migrant workers. (3) the mechanism analysis reveals that health level plays a part of intermediary effect in the impact of urban workers’ medical insurance on the labor supply of migrant workers, while the consumption level plays a masking effect in the impact of urban workers’ medical insurance on the labor supply level of migrant workers.

Key words: urban workers’ medical insurance, labor supply, migrant workers