Abstract: Objective To study cell proliferation and differentiation of myoblasts with the myostatin silenced. Methods siRNA expression vector targeting the myostatin gene was constructed, then siRNA expression vector was transfected into myoblasts. The expression of myostatin in the transfected myoblasts was determined by real-time quantitative RT-PCR and Western blot. Transfected myoblasts were seeded in dishes, harvested at the indicated times, and counted. Creatine kinase was measured for transfected myoblasts. Transfected myoblasts were shifted to differentiation medium containing low fetal bovine serum, myotube formation was observated at the indicated times. Results Real-time quantitative RT-PCR showed that the rate of silencing of myostatin in transfected myoblasts was 81.6% for the siRNA expression vector, it was also testified by Western blot. The number of myoblasts transfected with the siRNA expression vector increased, and creatine kinase activity elevated than in control cells (P<0.05). After 7 days of incubation in differentiation medium, control myoblasts showed formation of myotubes. By contrast, formation of myotubes was observated after 10 days of incubation in differentiation medium for transfected myoblasts under the same conditions. Conclusion Cell proliferation capacity of myoblasts increases, and differentiation is inhibited when the myostatin is silenced with siRNA. Considering the above findings, it is likely that it is an alternative therapy method for muscle atrophy by silencing the myostatin gene with the siRNA expression vector.