With increasing recognition of and concern about mental health problems in Chinese young adults, the factors that contribute to mental health in Chinese young adults are receiving growing attention. Prior research has documented that adult attachment styles may be a risk factor for depression and anxiety in Western societies. However, little is known about the relation between adult attachment and mental health problems in China. In addition, research on the underlying mechanism between adult attachment and mental health problems is limited. The present study aimed to examine (1) the relation between adult attachment and young adults’ mental health problems in China and (2) the mediating effect of self-esteem in the relation between adult attachment and young adults’ mental health problems in China. The study was based on a sample of 305 urban Chinese students who completed a questionnaire about their attachment styles, self-esteem, and general mental health. Structural equation modeling was used to test our hypotheses. The results showed that (1) Both anxious and avoidant attachment linked to mental health problems in China through the partial mediating effect of self-esteem; (2) Anxious adult attachment also directly and positively associated with mental health problems, and (3) Avoidant adult attachment directly and negatively associated with mental health problems. The findings are interpreted on the basis of Chinese cultural features.