The progresses on the study of neurotrophic factors such as neurotrophins and their functional receptors-tyrosine kinase receptors (Trks-TrkA, TrkB, TrkC) have been made rapidly. These factors can promote neuronal survival, outgrowth, differentiation and repairment of injury. New knowledge on the mechanism of inner ear development has been provided at both molecular and cellular levels by the application of immunohistochemistry, in situ hybridization and gene knock-out mice models in the study on the regulation of these neurotrophins and their receptors in the inner ear development. The application of exogenous neurotrophins has great clinical potential for the cure of hearing loss.