Objective To investigate the anxiety, depression and sleep quality of nurses in cardiovascular medicine in the coronavirus disease 2019 (COVID-19) outbreak, and to explore the effects of interventional psychological counseling and stress reduction training on mental health with a view of providing reference for relevant personnel. Methods A total of 60 nurses in the Cardiovascular Department of Chinese PLA General Hospital were selected and analyzed using Generalized Anxiety Disorder Scale (GAD-7), Patient Health Questionnaire-9 (PHQ-9) and Pittsburgh Sleep Quality Index (PSQI) in the aspects of post of duty, gender, marriage, and length of service. Meanwhile, nurses in the quarantine wards were given psychological counseling and stress reduction training, and an analysis was conducted on the interventional effects. SPSS statistics 17.0 was used for data analysis. Results Nurses in the quarantine and the transition wards suffered from higher degree of anxiety and depression than those in the general ward, female higher than male, the married higher than the unmarried, and the senior higher than the middle-aged and junior. The nurses in the transition and the general ward had better sleep than those in the quarantine ward, male better than female, and the middle-aged and junior than the senior. After intervention, the anxiety[(2.87±3.63) vs(1.73±2.15)], depression[(3.22±3.32) vs(1.82±1.74)] and sleep quality[(8.65±3.52) vs(5.82±2.58)] of the nurses in the quarantine ward were improved, the difference being statistically significant(P<0.05). Conclusion In the COVID-19 outbreak, nurses in the cardiovascular department vary in the levels of psychological stress, which can be improved by reasonable intervention.