BACKGROUND: COVID-19 has posed an unprecedented threat to public health and remains a critical challenge for medical staff, especially those who have been fighting against the virus in Wuhan, China. Limited data have been reported regarding the psychological status of these medical staff members. Therefore, we conducted this study to explore the mental health status of medical staff and the efficacy of brief mindfulness meditation (BMM) in improving their mental health. METHODS: A survey was conducted between April 18 and May 3, 2020. Upon completing the pre-test, participants in the treatment group received a 15-min BMM intervention every day at 8 p.m. Post-test questionnaires were completed after 16 days of therapy. The questionnaire comprised demographic data and psychological measurement scales. The levels of pre and post-test depression, anxiety, stress, and insomnia were assessed using the 9-item Patient Health Questionnaire, 7-item Generalized Anxiety Disorder Scale, Perceived Stress Scale, and Athens Insomnia Scale, respectively. RESULTS: A total of 134 completed questionnaires were received. Of the medical staff, 6.7%, 1.5%, and 26.7% reported symptoms of depression, anxiety, and insomnia, respectively. Public officials from military hospitals reported experiencing greater pressure than private officials (t = 2.39, p = 0.018, d = 0.50). Additionally, BMM treatment appeared to effectively alleviate insomnia (t = 2.27, p = 0.027, d = 0.28). CONCLUSIONS: The medical staff suffered negative psychological effects during the COVID-19 pandemic. BMM interventions are advantageous in supporting the mental health of medical staff.