To investigate the relationship between self-rated mental health and life Stress，core self-evaluations and coping style among Beijing citizens，we conducted a sample survey of 2455 Beijing Citizens from 82 communities in 16 districts in Beijing.Results showed that the higher the perceived life stress of citizens，the lower the overall level of their self-rated mental health；The higher the core self-evaluations of citizens，the more positive the coping style，the higher the overall level of their mental health.Further analysis showed that the impact of core self-evaluations on mental health was moderated by life stress，and core self-evaluations partly influenced self-rated mental health through coping style.The report put forward some suggestions for improving citizens' mental health.