Abstract
Migrant workers in China often experience employment instability due to limited labor protection and restricted access to formal institutions, which undermines both job security and social integration. Although trade unions are expected to support workers' employment, their role remains debated in the Chinese context. Using pooled data from the China General Social Survey (2010-2021), this study examines the effect of union participation on migrant workers' employment by applying a treatment effect model. The results indicate that union membership is significantly associated with a higher likelihood of non-agricultural employment. Mechanism analyses suggest that unions improve employment outcomes by enhancing labor rights protection, promoting formal contracts, and expanding social insurance coverage, thereby reducing perceived employment uncertainty and strengthening labor market attachment. These findings suggest that union participation is associated with improved employment outcomes, potentially through institutional and psychological pathways. However, it is important to acknowledge that unions may also serve as markers of pre-existing formalized employment environments.