Improving the subjective well-being of migrant workers has a boosting effect on building a moderately prosperous society in an all-round way. Based on the CGSS data in 2015,this paper constructs an o-logit model to investigate the main effect and interaction effect of migrant workers’ employment quality and social trust on subjective well-being,and uses the instrumental variable method to eliminate the possible endogenous problems. The results are as follows:1) The employment qualities of migrant workers have a significant effect on subjective well-being among which high work reward,short working hours,free working environment,clear job security and stable working state contribute greatly to migrant workers’ happiness. 2) Migrant workers with higher social trust have higher subjective well-being and the social trust of migrant workers has a differential order pattern. 3) There are interactive effects between migrant workers’work reward,working hours and their trust in neighbors,relatives and people who participate in amateur activities together. The results show that migrant workers’ trust in neighbors and relatives can enhance the positive impact of income on subjective well-being and trust in neighbors and people who participate in amateur activities can alleviate the negative impact of working hours on subjective wellbeing. Therefore,the government should increase the maintenance of migrant workers’ income and social security and enrich the spiritual life of migrant workers and other aspects to improve the happiness of migrant workers.