Objective To compare the effectiveness of patient-controlled intravenous analgesia with or without background infusion of dezocine plus flurbiprofen axetil injection in patients undergoing laparoscopic colorectal cancer operation. Methods Sixty patients scheduled for laparoscopic colorectal cancer surgery,35 males and 25 females,aged 18-65 years,ASA physical status Ⅰ or Ⅱ,were randomly divided into 2 groups:common-dose background infusion group(Group CB,n = 30),and no background infusion group(Group NB, n = 30). All patients were intravenously administered a PCA pump containing dezocine 0.6 mg/kg,flurbiprofen axetil 3 mg/kg and normal saline in a volume of 120 mL.Patients in Group CB were given background infusion rate of 2 mL/h with PCA bolus dose 2 mL,patients in Group NB were given PCA bolus dose 4 mL only.NRS scores, Ramsay sedation scores,pressing times,consumption of analgesic,supplementary analgesics,incidence of ad-verse reactions,time of first exhaust,time of first leaving bed and patients'satisfaction scores were recorded after surgery. The influence factors of time of first exhaust and time of first leaving bed were also analyzed. Results Compared with group CB,the NRS scores in group NB were higher both at rest and during movement(P<0.05), the Ramsay sedation scores in group NB were lower at 24 and 48 h after surgery(P<0.05),the pressing times in group NB were higher(P < 0.05),the consumption of analgesic in group NB were lower after surgery,and the incidence of using supplementary analgesics was higher(P < 0.05). No statistical difference was found on the in-cidence of adverse reactions between the two groups(P > 0.05). Moreover,the time of first leaving bed in group NB was longer than that in group CB(P<0.05).The satisfaction scores in group NB was lower than that in group CB(P<0.05).The main influence factors of the time of first leaving bed were gender and NRS score during move-ment at 24 h after the operation(P<0.05).The main influence factors of the time of first exhaust were age,BMI and fluid infusion volume(P < 0.05). Conclusion Postoperative patient-controlled intravenous analgesia with background infusion of dezocine and flurbiprofen axetil injection was more efficacious and satisfactory,and more suitable in postoperative pain management.