OBJECTIVE： To investigate the influence of dexmedetomidine combined with fentanyl on analgesic effects and hemodynamics of orthopedics patients after surgery. METHODS： A total of 80 patients undergoing orthopedics surgery were randomly divided into observation group （40 cases） and control group （40 cases）. Observation group was given patient-controlled analgesia （PCA） of Dexmedetomidine hydrochloride injection+Fentanyl citrate injection， maintaining analgesia for 48 h. Control group was given PCA of Fentanyl citrate injection， maintaining analgesia for 48 h. The MAP， SpO2， HR， VAS and the occurrence of ADR were observed in 2 groups from the application of multi-function monitor to connecting to PCA （T0）， 12 h after connecting （T1） and 48 h after connecting （T2）. RESULTS： At T0， there was no statistical significance in VAS score between 2 groups （P＞0.05）. VAS scores of 2 groups at T1-2 were significantly higher than at T0. Those of 2 groups at T1 were significantly higher than at T2； but the observation group was significantly lower than the control group， with statistical significance （P＜0.05）. There was no statistical significance in MAP， SpO2 or HR between 2 groups at different time points （P＞0.05）. The incidence of respiratory depression， sharp pain， nausea and vomiting， hypotension in observation group were significantly lower than control group， with statistical significance （P＜0.05）. CONCLUSIONS： Dexmedetomidine combined with fentanyl show significant analgesic effect after orthopedics surgery， and have no effect on hemodynamics with good safety.