The behavior of labor supply especially overwork, has always been a concern of the society, and migrant workers are the main group of over workers. Meanwhile, migrant workers with low incomes are more likely to suffer from liquidity constraints. Against this background, this paper discusses the impact of liquidity constraints on the labor supply of migrant workers from both theoretical and empirical perspectives, and further analyzes the phenomenon of migrant workers’ overwork by constructing a theoretical model and using the China Household Finance Survey data（CHFS2017）. The results show that:（1）Migrant workers affected by liquidity constraints will increase their labor supply and are more prone to overwork.（2）Liquidity constraints will decrease the consumption expenditure and family assets of migrant workers. Therefore, migrant workers tend to increase labor time and labor intensity to reduce the negative impact of liquidity constraints on consumption and family assets, which will increase the possibility of overwork.（3）Heterogeneity analysis shows that, migrant workers with poor financial credit environment, poor protection of labor rights and interests, low incomes, high family support pressure, heavy social security contribution burden and high urban living costs, are more prone to increase labor supply and overwork while being affected by liquidity constraints.

The Report of the 19th National Congress of the Communist Party of China pointed out that insisting on ensuring and improving people’s livelihood during development is an inherent requirement for the high-quality development of China’s economy. Migrant workers are socially vulnerable groups that need to be paid attention to in the process of economic development. This paper discusses the labor supply behavior of migrant workers from the perspective of liquidity constraints, which enriches the theoretical research on the connection between financial market and labor market, provides a new perspective for analyzing the labor supply behavior of migrant workers, and provides policy enlightenment for alleviating the phenomenon of migrant workers’ overwork.

This paper argues that alleviating the phenomenon of migrant workers’ overwork can be considered from the perspective of not only labor market but also financial market to find solutions. The implementation of a series of combined policies by the government, such as optimizing the financial credit environment, protecting migrant workers’ labor rights and interests, raising migrant workers’ incomes, and reducing migrant workers’ family support pressure, social security contribution burden, and urban living costs, will be helpful to alleviate liquidity constraints and then reduce the phenomenon of migrant workers’ overwork.