Abstract: OBJECTIVE To retrospectively analyze potential inappropriate medication(PIM) used among the elderly outpatients, to analyze its related risk factors from the hospital and the departments, and to provide the reference for using rational drug in clinical practice. METHODS The elderly outpatients with 65 years old or over were collected from January to June 2016, and their PIMs were determined by Beers Criteria 2015. The χ² testing and multivariate logistic regression were conducted to analyze the related risk factors of PIMs, and its varieties of the elderly patients in different departments were evaluated. RESULTS A total of 182 431 cases were collected, in which the number of PIM prescription cases were 24 374(13.36%). The PIM cases were mainly distributed in cardiovascular medicine, neurology and psychiatry departments. The highest PIM incidence was 92.70% in psychiatric department. The most commonly prescribed drugs in PIM cases were diuretics, benzodiazepines and SSRIs, and their ratios of the total PIM cases were 34.57%, 27.77% and 14.90%, respectively. The PIM case numbers and incidences of these drugs were different in different departments. Compared with the PIM cases among different departments, it was found that the prevalences of PIMs were positively or negatively correlated with the age or disease number increasing in these departments, but the prevalences of PIMs were all positively correlated with the overall numbers of drugs. The PIM odds ratio in psychiatry department was maximal increased by 114.7%, which was 4.5 times as much as its in general medicine department(minimal increased by 25.4%). CONCLUSION The clinicians and pharmacists should pay attention to the PIM related factors of the elderly patients with the different prevalences of PIMs in different departments, screen the potential risk of drug use, and promote rational clinical drug use.