Objective To describe HIV/AIDS stress among newly HIV-infected men who have sex with men, and to investigate effects of HIV/AIDS stress on mental health and to explore the moderated role of social support between HIV/AIDS stress and emotional problems. Methods A survey involving SS-HIV, PHQ-9, GAD-7 and SSRS was conducted with a sample of 321 newly HIV-infected men who have sex with men newly identified by the Center for Disease Prevention and Control in Central South of China. Results Participants (n = 321) reported high levels of HIV/AIDS stress, especially from social problems. There was significant difference of HIV/AIDS stress among the participants of different household registration and HIV symptoms. The rates of depression and anxiety were 41.1% and 31.5%. Stress was positively correlated with emotional problems, while social support was negatively correlated with emotional problems, social support didn't play a moderated role on the relationship between HIV/AIDS stress and emotional problems. Conclusions Newly HIV-infected men who have sex with men generally are reported high levels of HIV/AIDS stress, depression and anxiety. Management interventions targeting social support and stress among newly HIV-infected men who have sex with men are indicated.