Objective To investigate the current status of potentially inappropriate medications (PIM) for elderly inpatients with mental illness in a psychiatric hospital. Methods Based on the 2017 edition of “Judgment Standards for Potentially Inappropriate Medications for the Elderly in China”, we retrospectively analyzed the PIM by investigating the clinical diagnosis and medication status of 125 elderly psychiatric inpatients in March 2021. Results Among 125 subjects, the average age was (73.31±7.87) years, and the average medication was (6.62±2.68). There were 101 patients (80.80%) had 140 items of PIM, 81 patients (64.80%) used a total of 103 items of A-level warning drugs, 33 patients (40.74%) used a total of 37 items of B-level warning drugs; there were 39 high-risk drugs(27.86%), 101 low-risk drugs (72.14%); the drugs with top three PIM incidence were olanzapine, risperidone and lorazepam; 12 patients had 4 PIMs related to the disease state. Conclusions The incidence of PIM in this hospital is relatively high. Doctors and pharmacists should be advised to increase their efforts to reduce the proportion of PIM, reduce the incidence of adverse reactions, improve medication safety, and promote rational drug usage.