A sensorless control method for synchronous reluctance motor based on super-twisting sliding mode adaptive observer was presented for the problems about low accuracy of speed estimation and poor dynamic performance about the sensorless control based on model reference adaptive system. Firstly, the inductance nonlinear model of synchronous reluctance motor was constructed by finite element simulation, and the inductance parameters were updated in real time according to different operating conditions of the motor, so as to improve the accuracy of the model in the observer. On this basis, the super-twisting sliding mode algorithm was used to replace the PI adaptive link, and the super-twisting sliding mode adaptive observer was constructed with the selected linear compensation matrix to reduce the estimation error. Finally, the integrated global fast terminal sliding mode speed controller was introduced to improve the dynamic performance of the system. Simulation and experimental results indicate that, compared to the sensorless system based on model reference adaptive control, the proposed strategy achieves a faster speed response and smaller overshoot during the startup phase, ensures smoother motor operation, exhibits minimal speed fluctuations and faster speed error convergence under sudden load changes, and demonstrates higher speed and rotor position identification accuracy throughout the entire variable-speed operation phase, thereby showcasing excellent dynamic and steady-state performance for high-performance motor operation.