Background To investigated the effects of sufentanil in combination with flurbiprofen axetil and dexmedetomidine for patient-controlled intravenous analgesia (PCIA) on patients after open gastrointestinal tumor surgery, and compared this combination with traditional PCIA with pure opioids or epidural analgesia (PCEA). Methods Patients (n = 640) who underwent open gastrointestinal tumor surgery and received patient-controlled analgesia (PCA) were included. According to the type of PCA, patients were assigned to three groups: MPCIA (PCIA with sufentanil, flurbiprofen axetil, dexmedetomidine and metoclopramide), OPCIA (PCIA with sufentanil, tramadol and metoclopramide) and PCEA group (PCEA with sufentanil and ropivacaine). The characteristics of patients, intraoperative use of analgesics, postoperative visual analogue scale (VAS), postoperative adverse reactions and postoperative recovery were collected. The primary outcome was postoperative VAS score. One-way ANOVA, Kruskal-Wallis H test, Fisher exact probability method, and binary logistic regression analysis were used for analysis. Results There were no significant differences in the characteristics of patients, operation time, tumor site and the use of postoperative rescue analgesics among the groups. In the first two days after open gastrointestinal tumor surgery, the VAS (expressed by median and interquartile range) of MPCIA (24(th) h, resting: 1,1; movement: 3,2. 48(th) h, resting: 0,1; movement: 2,1.) and PCEA (24(th) h, resting: 0,1; movement: 2,1. 48(th) h, resting: 0,1; movement: 2,2.) groups were significantly lower than those of OPCIA group (24(th) h, resting: 2.5,2; movement: 4,2. 48(th) h, resting: 1.5,1.75; movement: 3,1.) (all p < 0.01). The incidence of postoperative nausea and vomiting in MPCIA group was 13.6% on the first day after surgery, which was significantly higher than that in PCEA group. There was no significant difference in the incidence of other postoperative adverse events. Higher intraoperative sufentanil dosage (OR (95%CI) = 1.017 (1.002-1.031), p = 0.021), lower body mass index (OR (95%CI) = 2.081 (1.059-4.089), p = 0.033), and tumor location above duodenum (OR (95%CI) = 2.280 (1.445-3.596), p < 0.001) were associated with poor postoperative analgesia. Conclusions The analgesic effects of PCIA with sufentanil in combination with flurbiprofen axetil and dexmedetomidine on postoperative analgesia was better than that of traditional pure opioids PCIA, and similar with that of PCEA.