OBJECTIVE： To promote the implementation of the pre-prescription review work， and to ensure the rational drug use of patients. METHODS： With the idea of PDCA （Plan， Do， Check， Action） cycle management， the phased improvement of three PDCA cycles was gradually implemented in the operation of the pre-prescription review system， aiming at the establishment of the working mode of the prescription review work， the improvement of the rules of knowledge base in the review system and the improvement of the ability of pharmacists to review prescriptions. The operation results of the system were evaluated by comparing the irrational prescription rate of outpatient pharmacies before and after the operation of pre-prescription review system. RESULTS： Through adopting the prescription review mode of “rigid” and “flexible” interception， regular revision of knowledge base rules， regular training and examination of prescription pharmacists， pre-prescription review system operated smoothly， and the pre-prescription review work was carried out in the process of continuous improvement. In the three PDCA cycles， the irrational rate of prescriptions decreased significantly， such as after the first PDCA cycle， the irrational rate of TCM outpatient prescriptions decreased from 22.0％ （1 393/6 332） in Jan. 2017 to 7.4％ （416/5 627） in Jun. 2017； after the second PDCA cycle， the irrational rate of outpatient prescriptions in hospital decreased from 4.87％ （5 244/107 691） in Mar. 2018 to 2.21％ （2 219/100 412） in Aug. 2018. After the third PDCA cycle， the percentage of over-treatment course prescriptions in total prescriptions decreased from 16.97％ （15 728/92 684） in Jun. 2018 to 5.55％ （5 394/97 275） in Sept. 2018. CONCLUSIONS： The pre-prescription review system can effectively intercept and interfere with irrational prescriptions， and PDCA cycle management can effectively promote the operation of the pre-prescription review work.