A finite-time disturbance observer based full-order sliding-mode control （FTDO-FOSMC） method is proposed for the permanent magnet spherical actuator （PMSA） motion system affected by external disturbances and model uncertaintys， First， the dynamic model of the PMSA is established. The uncertainty includes modeling errors and external disturbances. Second， a finite time disturbance observer is designed to quickly and accurately estimate the system’s lumped disturbances. Third， a full-order sliding mode surface is designed for the permanent magnet spherical actuator， which reflects its full-order dynamic characteristics when the ideal sliding mode moves， instead of the reduced-order dynamic characteristics in the traditional sliding mode control system. Finally， the stability of the closed-loop system of the proposed control method is proved by Lyapunov's theorem. The simulation and experiment results show that the proposed controller has good dynamic characteristics and anti-disturbance ability under lumped disturbances.