OBJECTIVE： To learn the situation of off-label drug use in psychiatric hospital and provide baseline data for formulating off-label drug use policy. METHODS： The stratified random sampling was conducted to select outpatient prescriptions from our hospital in 2015. According to drug instructions， all off-label drug use was analyzed in the following aspects， the category of off-label drug use， disease diagnosis， the category of doctors. RESULTS： Totally 7 300 prescriptions were collected， accounting for 2.6％ of total in outpatient pharmacy in 2015. There were 715 prescriptions of off-label drug use， accounting for 9.8％ of total. Top 3 types were extra-indication （64.1％）， extra-DDDs （17.3％） and extra-suitable population （12.2％）； top 3 disease types were MBD （22.0％）， depression （21.7％） and Alzheimer’s disease （16.3％）. Inpatient physicians took up the first place among all physicians who prescribed prescriptions. CONCLUSIONS： Off-label use in outpatient pharmacy is common in our hospitals. The physicans with primary title should be considered as break through point of improving off-label drug use， and great importance should be attached to the classification and evaluation of off label drug use prescriptions.