OBJECTIVE： To provide reference for the improvement of rational drug use in outpatient department of our hospital. METHODS： 24 947 prescriptions were selected from outpatient pharmacy of our hospital during Mar. 2015-Mar. 2016， and the irrational prescriptions were summarized and analyzed. RESULTS： There were 1 342 unreasonable prescriptions， accounting for 5.38％. They mainly manifested as overdosage， nonstandard writing of clinical diagnosis， wrong brand name， dosage and route of administration， inappropriate complications， inappropriate route of administration and dosage， inappropriate drug， inappropriate usage and dosage， repeated drug use， incompatibility. The most common irrational types were nonstandard writing of clinical dragnosis （22.88％） and inappropriate usage and dosage （61.18％）. CONCLUSIONS： Irrational drug use still exists in the outpatient prescriptions in our hospital. It is suggested to take countermeasures timely， and continuously improve and perfect the intervention measures of unreasonable prescriptions， improve the quality of prescriptions and the level of rational drug use， in order to ensure the medical safety.