Objective · To investigate the effect of medium frequency electrical stimulation on the expression of neurotrophin-3 (NT-3) in the mandibular protrusion of SD rats. Methods · Sixty male SD rats were randomly divided into three groups (n=20): blank control group, conditioned control group (treated with functional appliance, but without medium frequency electrical stimulation) and experimental group (treated with functional appliance and medium frequency electrical stimulation). Five rats in each group were sacrificed on the 3rd, 7th, 14th and 21st day to prepare the samples of masseter muscle. Immunohistochemistry and quantitative real-time PCR methods were used to detect the protein and mRNA expressions of NT-3 in the masseter muscle of rats. Results · The protein and mRNA expressions of NT-3 were increased firstly and then decreased in the conditioned control group and the experimental group, compared with those in the blank control group. Moreover, the protein and mRNA expressions of NT-3 in the conditioned control group were still higher than those in the blank control group on the 21st day (both P<0.05), while the protein and mRNA expressions of NT-3 in the experimental group almost returned to the normal level on the 21st day. Conclusion · Medium frequency electrical stimulation may accelerate the rate of neuromuscular reconstruction and shorten the time of functional orthopedic therapy in rats.