To evaluate the effect of intraperitoneal hyperthermo-chemotherapy (IPHC) on immunologic function of patients with gastrointestinal malignant tumor (GMT). The authors determined the serum T-lymphocyte subsets (T-LS) and interleukin-2 receptor (sIL-2R) of 32 patients with GMT after IPHC, and compared the two indexes with 20 healthy control group. Results: Before IPHC the serum CD＋3, CD＋4, CD＋8 and CD＋4/CD＋8 were higher and sIL-2R were lower than control group, after IPHC, CD＋3, CD＋4, CD＋8 and CD＋4/CD＋8 increased obviously (Ｐ＜0.01) and the serum sIL-2R decreased significantly (Ｐ＜0.01). Conclusion: The IPHC can improve the patients immunologic function.