OBJECTIVE：To explore the role of pharmacists i n developi ng the outpatient and emergency prescription pre-audit with the help of rational drug use software. METHODS ：With the help of rational drug use software ，outpatient and emergency prescription pre-aduit was conducted during Jan.-Apr. 2020；the intervention effects of irrational prescriptions were analyzed. The prescriptions from Sept. to Dec. in 2019 were included in the control group （only for post review ），and the prescriptions from Jan. to Apr. in 2020 were included in the intervention group （pre-audit and post review ）；the unreasonable prescriptions were compared before and after the intervention. The prescriptions intercepted by the software system from Nov. to Dec. in 2019 were further selected as the interception control group ，and the prescriptions intercepted from Jan. to Feb. in 2020 were selected as the interception intervention group ；the interception situation of prescriptions before and after the intervention was compared ，and the influence of pre-audit on physicians ’prescription behavior was evaluated. In addition ，108 992 prescriptions in Apr. 2020 were selected for post review using the traditional model （i.e. complete manual audit ）and the information model （i.e. software-assisted manual audit ）respectively；the effects of two models were compared. RESULTS ：From Jan. to Apr. in 2020，a total of 2 393 prescriptions were pre-audited by pharmacists ，among which 1 387 prescriptions were reasonable （57.96％）and 1 006 prescriptions were unreasonable and intervened （42.04％）. After pharmacist intervention ，983 prescriptions were modified by doctors ，and the success rate of intervention was 97.71％ . Compared with control group ，unreasonable rate of outpatient and emergency prescriptions，that of each type of prescriptions were all decreased significantly （P＜0.001）. Compared with interception control group（1 402 pieces），the number of intercepted prescriptions （721 pieces）was significantly reduced in interception intervention group （P＜0.001）. Compared with traditional model ， the number of prescriptions requiring manual post review and E-mail：xss306@126.com “false positive ” prescriptions were decreased significantly # under information model ， and the number of discovered unreasonable prescriptions were increased significantly （P＜ 0.001）. CONCLUSIONS ：With the help of rational drug use software ，prescription pre-audit by pharmacists can significantly improve reasonable rate of outpatient and emergency prescriptions. The work intensity of pharmacists in post review of prescriptions can be reduced and the accuracy of prescription review can be improved in the information mode.