This paper investigates the speed regulation problem of permanent magnet synchronous motor (PMSM) drive based on backstepping control and nonlinear disturbance observer. By introducing the backstepping control, the single-loop controller is designed instead of the traditional cascade structure, in which, speed and current controller are combined together by recursive design. However, the standard backstepping control method cannot achieve a satisfying behavior in the presence of the disturbance and parameter uncertainties. Unlike the existing adaptive backstepping control method, a nonlinear disturbance observer is designed to estimate the lump disturbance, which includes the matched and mismatched disturbance in the system. Through disturbance estimation and feed-forward compensation, the robustness of the controller is improved effectively. The stability of the system is also proved. Finally, simulation and experiment are implemented with real-time interface (RTI) based on dSPACE. Compared with PI control method, the proposed composite backstepping controller has fast transient response and strong robustness for all disturbance in various conditions.