Background: Prior studies on migrant workers have explored the effect of their subjective social status and job satisfaction on their mental health, respectively or combined, as well as how their subjective social status affects their job satisfaction. Nonetheless, few have accounted straightforwardly and holistically for the mechanism of interaction between subjective social status, job satisfaction and mental health amongst migrant workers. Aims: Taking migrant workers in China as the object of study, we intended to probe the longitudinal links between their subjective social status, job satisfaction and mental health, in particular, their job satisfaction as a longitudinal mediator therein. Method: Using the three-wave data from the 2014, 2016 and 2018 China Labour-force Dynamics Survey, we defined migrant workers as labourers aged 15 to 64 with agricultural hukou and engaged in non-agricultural work in urban areas. The final valid sample comprised 2,035 individuals. Latent growth models (LGMs) were applied to test the hypothesised relationships. Results: The LGMs based on bootstrapping showed that amongst migrant workers the subjective social status, job satisfaction and mental health tended overall to grow linearly and that the job satisfaction longitudinally mediated between the subjective social status and mental health. Conclusions: The findings may enlighten policymaking to elevate migrant workers mentally and inform future studies on theoretical and practical fronts.