With the aim of improving the robust tracking performance of permanent magnet synchronous motor (PMSM) drive systems, an indirect adaptive robust control strategy based on adaptive extended state observer (AESO) is developed in this paper. Firstly, the parameter estimation process is separated from the controller design, and the indirect adaptive law driven by the system input and output is adopted to guarantee the convergence and accuracy of parameter estimation. Secondly, an AESO is established to estimate the unmodeled characteristics and disturbances in the system, and the performance of disturbance estimation and compensation is improved by dynamically adjusting the observer gain. Finally, an adaptive tracking controller is synthesized using the backstepping method, and its stability is proven using Lyapunov analysis. Simulation results demonstrate the effective performance improvement of the synthesized controller for tracking control.