OBJECTIVE： To investigate the effects of preemptive analgesia of parecoxib-sodium for radical mastectomy of breast cancer. METHODS： A total of 60 female patients underwent selective radical mastectomy of breast cancer under general anesthesia were randomly divided into observation group （40 cases） and control group （20 cases）. 15 min before anesthesia induction， observation group was given intravenous injection of Parecoxib-sodium for injection 40 mg. Control group was given intravenous injection of 0.9％ Sodium chloride injection 5 mL. The pain visual analogue scale （VAS）， the frequency of patient controlled intravenous analgesia （PCA） and ADR were observed between 2 groups at different time points after surgery. RESULTS： VAS scores of observation group were significantly lower than those of control group 2，4，6，8 h after operation， and the frequency of PCA 0-4， 4-12， 12-24， 24-36 h after operation was significantly lower than control group， with statistical significance （P＜0.05）. There was no statistical significance in the incidence of ADR between 2 groups （P＞0.05）. CONCLUSIONS： The preemptive analgesia of parecoxib-sodium can effectively reduce pain degree of patients with breast cancer after radical mastectomy， the frequency of PCA， and do not increase the occurrence of ADR.