To find out the reasons why patients still need to use rescue analgesics frequently after gastrointestinal tumor surgery under the patient-controlled intravenous analgesia (IV-PCA), and the different abdominal surgery patients using the difference of analgesics.A total of 970 patients underwent abdominal operation for gastrointestinal tumors were included. According whether patients used dezocine frequently for rescue analgesics within 2 days after surgery, they assigned into two groups: RAN group (Patients who did not frequently use rescue analgesia, 406 cases) and RAY group (Patients who frequently used rescue analgesia, 564 cases). The data collected included patient's characteristics, postoperative visual analogue scale (VAS), nausea and vomiting (PONV), and postoperative activity recovery time.No differences were observed in the baseline characteristics. Compared with the RAN group, patients in the RAY group had a higher proportion of open surgery, upper abdominal surgery, VAS score at rest on the first 2 days after surgery and PONV, and a slower recovery of most postoperative activities. Under the current use of IV-PCA background, the proportion of rescue analgesics used by patients undergoing laparotomy and upper abdominal surgery was as high as 64.33% and 72.8%, respectively. Regression analysis showed that open surgery (vs laparoscopic surgery: OR: 2.288, 95% CI: 1.650-3.172) and the location of the tumor in the upper abdomen (vs lower abdominal tumor: OR: 2.738, 95% CI: 2.034-3.686) were influential factors for frequent salvage administration.In our patient population, with our IV-PCA prescription for postoperative pain control, patient who underwent open upper abdominal surgery required more rescue postoperative analgesia.© 2022. The Author(s).