Aiming at the problems that the traditional sliding mode reaching law causes the system to have chattering phenomenon, slow convergence speed and unsmooth dynamic response, a multi-power sliding mode reaching law is proposed. The reaching law is based on three power term coefficients. The different stages of the system approach process are adjusted in a targeted manner, so that the convergence speed of the system dynamic response process is greatly improved, and there is no chattering phenomenon. The theory verifies its existence, reachability and stability, and the approach is derived in detail Speed and interference stability boundary. Taking the spacecraft attitude maneuvering control system as an example, the comparison simulation results show that under the reaching law, the dynamic process of the system is greatly improved and the chattering is eliminated, and there is model uncertainty and additional interference Under the action, the system can still quickly converge to the neighborhood near the equilibrium point.