<p>Childhood socioeconomic status (CSES) is known to have a lasting influence on individuals’ mental health. However, the mechanism underlying this relationship was not clear. The purpose of this study was to examine the roles of perceived parental autonomy support (PPAS) and core self-evaluations (CSE) in the relationship between CSES and mental health in two independent samples of Chinese emerging adults. In Study 1, a total of 511 participants (<i>M</i> = 20.14, <i>SD</i> = 1.61) from two universities in Hunan, China participated in this study. They completed questionnaires measuring CSES, PPAS, CSE, negative emotions (NE) and life satisfaction (LS). The results showed that high levels of CSES was related to decreased NE and increased LS. Mediation analysis further indicated that a serial mediating role of PPAS and CSE in the relationship between CSES and mental health. To test the stability and generalizability of the results in Study 1, we further conducted a Study 2, which including 542 participants (<i>M</i> = 20.15, <i>SD</i> = 1.60) from five universities in Hunan. Participants completed the same questionnaire as in study 1 and provided their objective socioeconomic status (SES). The serial mediating results remained significant after controlling objective SES. The implications for future research and the possible prevention and interventions for enhancing emerging adult mental health were discussed.</p>