Due to the nonlinear and strong coupling dynamic model of a direct-drive permanent magnet spherical motor (PMSM) dynamics system, an adaptive backstepping sliding mode controller is developed. Firstly, by using the second Lagrange equation and the Carden angle coordinate transformation, the PMSM rotor dynamic model is achieved. Secondly，the proposed approach effectively combines the design techniques of backstepping and the sliding mode control in order to restrain the effects of the external disturbance and parameter variations. Adaptive law of the external disturbance upper bound can be derived based on the Lyapunov-like design. Moreover, a novel reaching law is used to overcome the chattering phenomenon. Finally，simulation studies prove that the control scheme has high accuracy, rapid response and strong robustness.