Motor function development is a necessary condition for later life. It is closely related to cognitive psychological development1. As an important white matter reflecting the motor function, clarify the asymmetry of corticospinal tract (CST) development, which is of great significance for revealing the developmental of behavior and exploring the mechanism of disease2. This study aims to use DKI parameters investigate the asymmetry of CST development. Our results suggest that from 0-13 years old, there is hemispheric asymmetry in the development of CST, and they show left-sided dominance ;the asymmetry of CST appears at 6 months.