OBJECTIVE：To explore the role of clinical pharm acists in anti-infective therapy in patients with septic shock in the ICU. METHODS ：A total of 180 patients with septic shock were retrospectively collected from ICU of Chongqing Qianjiang Central Hospital during Jan.-Dec. 2018. According to whether clinical pharmacists participated in anti-infective therapy in the whole process，the patients were divided into intervention group （92 cases）and control group （88 cases）. Both groups were given routine treatment according to clinical diagnosis ；on this basis ，clinical pharmacists participated in the whole anti-infective therapy of the intervention group ，including participating in pharmaceutical rounds ，formulating anti-infective programs ，guiding nurses to implement anti-infective plan ，and providing pharmaceutical care for patients. The effectiveness ，safety and antibiotics clinical use indexes（such as proportion ，treatment course and cost of key monitored drugs ）were evaluated in 2 groups. RESULTS ：The cure rate of intervention group （98.91％）was significantly higher than that of control group （93.18％），while the incidence of ADR in the intervention group （8.70％）was significantly lower than control group （23.86％）. The use of antibiotics types was more rational（the proportion of carbapenems used in intervention group and control group were 20.65％，36.36％；those of quinolones were 15.22％，28.41％，respectively）；the duration of antibiotics use in the intervention group [ （15.18±2.25）d] was significantly shorter than control group [ （19.84±3.81）d]. The cost of antibiotics per capita [ （2 846.99±712.48）yuan] was significantly lower than control group [ （3 991.26±577.82）yuan]，with statistical significance of all above （P＜0.05 or P＜0.01）. CONCLUSIONS ： Clinical pharmacists participating in the anti-infective treatment of ICU patients with septic shock and providing pharmaceutical care，can improve the anti-infective effect ，reduce adverse drug reactions and drug-induced diseases ，optimize the use of antibiotics and reduce medical cost.