The significance of socioeconomic status (SES) in child mental health is well-established in Western populations; however, there is little evidence on this topic in Chinese populations. The possibility that Chinese families with different SES elicit different parenting practices that cause positive or negative child mental health outcomes warrants further investigation. This study examined the associations of SES, parenting practices, and child mental health among 1401 Chinese school children and their parents residing in Shanghai. SES was measured by a composed index of parental education levels, occupations, and household incomes. The Alabama parenting questionnaire (APQ; child version) and the strengths and difficulties questionnaire (SDQ; parent version) were used to assess parenting practices and child mental health. We also explored the underlying mechanisms between parental SES and the mental health of children by testing different parenting practices as mediators of the relationships. The results showed that a higher SES is positively associated with better mental health in children. Positive involvement and deficient monitoring can mediate the relationship between SES and child mental health outcomes. Negative discipline did not significantly mediate the above relationship. The results highlight the significance of positive involvement and sufficient monitoring in promoting children's mental health and provide evidence for designing effective programs to improve parenting skills.