Objective:To explore the influence of patient-controlled intravenous analgesia(PCIA)with morphine on early post-operative cognitive function in the elderly patients undergoing abdominal surgery with target control infusion(TCI)/total intra-venous anesthesia(TIVA).Methods:A total of 120 patients matched with the inclusion criteria were randomly divided into PCIA group with morphine(n=60)and control group(n=60).All the patients underwent abdominal operation with TCI/TI-VA.Pain intensity at 24 h and 48 h after the operation were evaluated by visual analogue scale(VAS).Mini-mental state examination(MMSE)scores were recorded at 24 h before the operation and 24 h,48 h,72 h after the operation,in order to as-sess cognitive function and incidence of POCD.Results:Scores of VAS in PCIA group were significantly lower than those in control group at 24 h and 48 h after the operation(P <0.01).The incidence of postoperative cognitive dysfunction(POCD)at 72 h after the operation in PCIA group was lower than that in the control group (P <0.05),and recovery of postoperative cog-nitive function in PCIA group was better than that in the control group(P <0.05).Conclusions:PCIA with morphine could re-duce the incidence of POCD in the elderly patients undergoing abdominal surgery and improve postoperative cognitive function.