〔Abstract〕 Objective To analyze the effect of pharmacists' intervention on the changes of doctors' prescribing behavior in inpatients with abnormal liver function under pre-examination drug warning system. Methods The medical order data of 67 inpatients with abnormal liver function who were issued pre-examination drug warnings by the drug clinical decision support system (CDSS) of Shenzhen Second People's Hospital from January to December 2019 were selected. According to whether or not pharmacists intervened (pharmacists reminded doctors to adjust medical orders under the CDSS drug warning), 26 cases were divided into the pharmacists intervention group and 41 cases were divided into the pharmacists non-intervention group. The changes in prescribing behavior were compared between the two groups. Results CDSS issued 98 drug warnings to 67 patients with abnormal liver function. There were 11 kinds of drugs involved in CDSS warning for patients with abnormal liver function, among which Parecoxib injection and esomeprazole injection accounted for the most, 25.51% and 22.45% respectively. The modification rate of doctors' prescription behavior in the pharmacist intervention group was 65.39%, which was higher than that in the pharmacist nonintervention group (34.15%), and the difference was statistically significant (P < 0.05). Conclusion Pharmacists' intervention with pre-examination drug warning system can significantly promote the change of doctors' prescribing behavior in patients with abnormal liver function.