Abstract: OBJECTIVE To investigate the effects of PDCA cycle on the continuous quality improvement of the outpatient and emergency department near miss prescriptions in hospital. METHODS A retrospective analysis was conducted on the near miss prescriptions which were reported by the pharmacists in the outpatient and emergency department of Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University in 2016. PDCA cycle method was adopted for the continuous improvement, then the ratio of near miss prescriptions, the incidence of errors in usage and dosage, the success rate of near miss prescription modification as well as other indicators in each stage of this project were compared and analyzed. RESULTS After implementing PDCA cycle, the proportion of near miss prescriptions had gradually decreased since the second quarter of 2017. Compared with the reported near miss prescriptions in the outpatient and emergency departments in 2016, the prescription proportion of errors in usage and dosage was decreased from 84.5% to 41.9%, the success rate of near miss prescription modification was >90%, while the ratio of prescriptions with incomplete diagnosis was increased from 2.9% to 44.0%. CONCLUSION By adopting PDCA cycle, the incidence of errors in usage and dosage of near miss prescription is decreased, the success rate of near miss prescription modification is increased, the incomplete diagnosis of near miss prescription is effectively exposed, while the intervention intensity of near miss prescriptions is strengthened, and then the medication safety of the outpatient and emergency patients is improved.