OBJECTIVE： To observe the effects of parecoxib preemptive analgesia combined with postoperative epidural analgesia on hip replacement and immune function. METHODS： Totally 86 patients undergoing unilateral hip replacement selected from Xining Third People’s Hospital during Jan. 2014- Jun. 2016 were divided into observation group and control group according to random number table， with 43 cases in each group. Two groups underwent unilateral hip replacement under spinal epidural anesthesia. Observation group was given Parecoxib sodium for injection 40 mg intravenously 30 min before the end of surgery. Control group was given constant volume of normal saline intravenously. Both groups were given epidural analgesia pump （Ropivacaine hydrochloride injection 150 mg+ Ondansetron hydrochloride injection 16 mg+Dezocine injection 10 mg， added into normal saline to 100 mL） after surgery with dripping speed of  2 mL/h and patient-controlled time of 15 min. The hemodynamic indexes， analgesic effect， T lymphocyte subsets and NK cells levels were compared between 2 groups at different time points as well as the occurrence of ADR after surgery. RESULTS： Two patients of observation group and one patient of control group withdrew from the study. Before surgery， there was no statistical significance in MAP and HR between 2 groups （P＞0.05）； 12， 24 h after surgery， MAP and HR of control group were significantly increased and higher than observation group， with statistical significance （P＜0.05）. There was no statistical significance in MAP and HR of observation group at different time points compared to before treatment； there was no statistical significance in MAP and HR between 2 groups immediately after surgery， 48 h after surgery （P＞0.05）. There was no statistical significance in VAS score between 2 groups immediately after surgery （P＞0.05）； 6， 12， 24， 48 h after surgery， VAS scores of observation group were significantly lower than those of control group， with statistical significance （P＜0.05）. There was no statistical significance in CD3+， CD4+， CD4+/CD8+ and NK cells levels between 2 groups before surgery （P＞0.05）. CD3+， CD4+ and NK cells levels of 2 groups immediately after surgery， CD3+， CD4+， CD4+/CD8+ and NK cells levels of 2 groups at 12， 24 h after surgery， CD3+ and CD4+ of control group at 48 h after surgery all changed significantly； CD3+， CD4+， CD4+/CD8+ and NK cells levels of observation group at 12， 24 h after surgery were significantly higher than those of control group， with statistical significantly （P＜0.05）. There was no statistical significance in the incidence of ADR between 2 groups （P＞0.05）. CONCLUSIONS： The parecoxib preemptive analgesia combined with postoperative epidural analgesia shows good analgesic effect for hip replacement patients， keeps their hemodynamics stable and protects immune function to certain extent with good safety.