Background: The psychological status of men who have sex with men (MSM) as a vulnerable population during COVID-19 is worthy of attention. However, studies of Chinese MSM are limited. The aim of this study was to investigate the psychological status and influencing factors of MSM population and to provide a scientific basis for this group to actively respond to public health emergencies. Methods: From June to September 2020, we conducted an online survey. MSMs were recruited through collaboration with non-governmental organizations (NGOs) and peer recommendations. The variables we collected included four aspects: demographic and HIV-related characteristics; COVID-19-related knowledge, attitudes, and behaviors; COVID-19-related risk perception; epidemic exposure. The psychological status was assessed by the Psychological Questionnaire for Emergent Events of Public Health (PQEEPH), which defined the psychological status as five primary disorders: depression, neurasthenia, fear, anxiety, and hypochondria. Multivariate logistic regression was used to explore the influences of COVID-19-related factors on the psychological status. Results: We surveyed 412 MSM online during COVID-19. The five psychological status of high-risk states accounted for 16.99% (depression), 14.08% (neurasthenia), 16.75% (fear), 16.50% (anxiety), and 18.20% (hypochondria), respectively. Not being well-informed about the causes of COVID-19 (p = 0.020) and having experienced epidemic exposure (p = 0.006) were able to promote the occurrence of depression. Lack of knowledge of the curative effect of COVID-19 has a higher risk of occurrence neurasthenia (p < 0.001). Being afraid of the novel coronavirus (p < 0.001) promoted fear. The perceived prevalence of the epidemic (p = 0.003), being more susceptible to COVID-19 (p < 0.001), and not being well-informed about the causes of COVID-19 (p = 0.005) had a positive effect on anxiety. Considering that the epidemic was not effectively controlled (p = 0.017), being more susceptible to COVID-19 (p < 0.001) was a contributing factor to the hypochondria. Conclusions: The incidence of psychological disorders in Chinese MSM was higher than that in other groups during COVID-19. Factors associated with COVID-19 may cause a range of mental health problems in this population. Greater attention should be paid to the mental health status of special populations during the epidemic, and effective preventive education and intervention measures should be taken.