The purpose of this investigation was to evaluate the effect of transforming growth factor-beta (TGF-beta) on the efficacy of Schwann cell (SC) and on the repair of peripheral nerve defect. 50 ng x ml(-1) TGF-beta was shown to promote the proliferation of SC by MTT and flow cytometry (FCM) assay, and NGF synthesis in SC culture media was noted to be of significantly higher concentration by ELISA method (P<0.05). SCs mixed with bovine acellular matrix (BAM), fetal bovine serum and media based on definite ratio were injected into polylactideco-glycolide acid (PLGA)guide. 30 SD rats, each had a man-made sciatic nerve defect 15 mm long, were randomly divided into 3 groups: experiment group (PLGA conduit+SC+TGF-beta), control group(PLGA conduit+SC), and autograft group. After 16 weeks, it was demonstrated that the effect of the test group was not significantly different from that of the autograft group, but it was better than that of the control group by means of electrophysiological test and sciatic nerve function index (SFI). TGF-beta can promote not only the proliferation, but also the NGF synthesis of SC obviously. The use of exogenous TGF-beta in the repair of peripheral nerve defect may produce better curative effect.