Objective To provide the promoting effect of extract of leave Ginkgo biloba(EGb_(50))on nerve regeneration and the dose-effect relationship.Methods Sciatic nerve injury model was set up in 96 male Spraque-Daweiy rats and then randomly divided into four groups:normal saline (NS) group,the low dose EGb_(50) group (50mg?kg~(-1)?d~(-1)),the moderate dose EGb_(50) group (100 mg?kg~(-1)?d~(-1)) ,the high dose EGb_(50) group (200 mg?kg~(-1)?d~(-1)).Electrophysiological,histological examinations and functional eval- uation were used to assess nerve regeneration and the functional recovery in 2,4,6,8 weeks of operative inter- vals respectively.Results The recovery rate of sciatic functional index(SFI),tetanic tension,motor nerve conduction velocity,muscle cell cross-section area of triceps surae and the passing rate of myelinated nerve were significantly higher in EGb_(50) group in all the time point than in control(P＜0.01).Except the recovery rate of sciatic functional index (SFI),there was significant difference between high dose group and moderate, low dose group.(P＜0.01,P＜0.05).Conclusion EGb_(50) has the effect of promoting regeneration of in- juried peripheral nerve and the high dose can get the best result.