Objective To explore the mental health status of military personnel with closed-off management 1 year after the outbreak of coronavirus disease 2019 (COVID-19). Methods A total of 294 officers and soldiers with closed-off management were investigated with self-made questionnaire of demographic data, generalized anxiety disorder (GAD-7), impact of event scale-revised (IES-R), patient health questionnaire 9 (PHQ-9) and insomnia severity index (ISI) scale to explore the mental health status 1 year after the outbreak of COVID-19. The influencing factors were analyzed by multiple linear regression model. Results A total of 257 valid questionnaires were collected, with an effective rate of 87.4%. Overall, the prevalence of depressive, anxious, post-traumatic stress disorder (PTSD) and insomnia was 47.5% (122/257), 29.6% (76/257), 39.7% (102/257) and 30.4% (78/257), respectively. Multiple linear regression analysis showed that gender and self-esteem were the influencing factors of depression (β=0.145 and -0.544, both P<0.01) and anxiety (β=0.192 and -0.515, both P<0.01). Age, education level and self-esteem were the influencing factors of PTSD (β=0.233, 0.126 and -0.484, all P<0.05). Gender, education level and self-esteem were the influencing factors of insomnia (β=0.118, 0.135, and -0.456, all P<0.05). Conclusion Depression, anxiety, PTSD and insomnia appear in some officers and soldiers with closed-off management 1 year after the outbreak of COVID-19, suggesting attention is needed to the mental health of military personnel 1 year after the outbreak of COVID-19. Tailored psychological counseling and interventions should be given to improve the mental health level of soldiers during the epidemic.