OBJECTIVE： To investigate the current situation of unreasonable prescriptions in outpatient and emergency departments of our hospital， and to provide reference for rational drug use in the clinic. METHODS： The evaluation of outpatient and emergency prescriptions in our hospital during 2013-2015 were summarized and analyzed. Irrational prescriptions were divided into 3 categories， involving 19 items. The main， secondary and general factors of irrational prescriptions were analyzed by Pareto chart. RESULTS： Among 19 types of irrational prescriptions， main factors included unsuitable drug selection， inappropriate usage and dosage， inappropriate drug combination， prescribing not in accordance with the antibiotics management regulations， incomplete diagnosis. No indications of medication， drug dosage beyond the regulations of “three urgent seven slow”  were treated as the secondary factors. Other 12 items were general factors. CONCLUSIONS： According to the main and secondary irrational drug use types， clinical pharmacists should carry out effective intervention and pharmaceutical care to improve the level of rational drug use and ensure the safety of clinical drug use.