Object To compare the effects of intravenous dexmedetomidine combined with Ultrasound guided Lumbosacral Plexus block and epidural block in intertrochanteric femoral fracture treated with Proximal Femoral Nail Antirotation (PFNA) in elderly patients. Methods 60 patients of ASA Ⅰ～Ⅱ, aged 65～75ys, suffering from intertrochanteric femoral fracture and undergoing elective PFNA fixation, were included in this study and randomly divided into 2 groups (n=30 each): lumbosacral plexus block group (Group L ) and epidural block group (Group E). Catheter was inserted into epidural space at L3-L4 interspaces and a total volume of 10-15ml of 0.5% ropivacaine was injected into epidural space in Group E. Patients in Group L received ultrasound-guided lumbar and sacral plexus block with 0.5% ropivacaine. 15min after block, a loading dose of dexmedetomidine 0.8µgkg-1 was infused over 15min, with a continuous dose of 1µgkg-1h-1. 20µg Fentanyl was given per time intravenous if any pain was felt. The mean arterial pressure (MAP), heart rate (HR), the consumption of fentanyl and ephedrine, the volume of fluid resuscitation and the incidence of adverse reactions were recorded. Results: 15min after blockage，the block effect were similar between the two groups. The duration of sensor and motor block of Group L were significantly longer than those of Group E(P＜0.05). And in group L, the duration of sensor block was longer than that of motor block(P＜0.05). The MAP was significantly attenuated in the Group E (P＜0.05). Patients in Group L(865±180)ml received less fluid than those in the Group E (1360±240)ml (P＜0.05) . Conclusion: The application of intravenous dexmedetomidine combined with Ultrasound-guided lumbosacral plexus block provides good effects in intertrochanteric femoral fracture treated with Proximal Femoral Nail Antirotation. There is a good advantage over epidural anesthesia.