Objective To analyze the composition and distribution of diseases in the psychiatric department of a tertiary TCM hospital, and provide theoretical basis for mental illness prevention and discipline construction. Methods A retrospective analysis of the first page data of 4178 psychiatric inpatient records in a Chinese hospital was performed. Gender, age, main diagnosis of discharge, length of stay, hospitalization expenses and other information were collected for statistical analysis. Results The top 5 diseases of inpatients in the psychiatric department were schizophrenia, depression, anxiety, acute stress response and epileptic psychosis, with a cumulative constituent ratio of 94.16%. the proportion of men (65.35%) suffering from schizophrenia was greater than that of women (34.65%); the proportion of female patients with depression, anxiety and acute stress reaction diseases was higher than that of male patients (P<0.001). On the whole, patients with mental illness between 31 and 45 years old accounted for the highest proportion (35.38%). Among them, patients with schizophrenia (46.62%), acute stress response (30.48%), and epileptic psychosis (49.38%) accounted for the largest proportion in the 31-45 year-old age group; depression patients accounted for the largest proportion in the 16-30 year-old age group (24.11%); anxiety patients in the over 60 years old age group accounted for the largest proportion (39.35%).Conclusion Schizophrenia is the main disease admitted in the psychiatric department. Men and young adults are high-risk groups. The prevention and treatment of this type of disease should be strengthened.