Abstract: Surgical stress, including pain, may induce cell immunodepression and can even affect postoperative recurrence of cancer. The influence of the postoperative analgesic buprenorphine and fentanyl on the perioperative cell immunity of gastric cancer patients was compared. Methods: A total of 40 patients undergoing surgery for gastric cancer were randomly divided into group B ( n = 20 ) with postoperative buprenorphine 0.3 μg·kg-1·h-1 as the experiment group and group F ( n = 20 ) with fentanyl 0.3 μg·kg-1·h-1 as the controls. Blood samples were collected before the surgery and at one day and three days after the surgery. T-cell subgroups CD3+, CD4+, CD8+, CD4+/CD8+, and NK cell were analyzed by flow cytometry, and the levels of cytokines INF-γ and IL-10 were determined using ELISA. Results: The surgical procedure and analgesic effects were similar between the two groups. There were reductions in the number of T cells and NK cells, and increased immunologic derangement, such as inflammatory cytokines, after the surgery. Compared with fentany l, buprenorphine was beneficial to the recovery of immune indices. Conclusion: Surgical stress can induce changes in T lymphocyte subsets, NK cells, and cytokines. Buprenorphine is more beneficial to immune recovery than fentanyl when used as a postoperative analgesic.