A design method for telescope AC servo control system, based on high-power permanent magnet synchronous motor, was proposed to meet the requirement of low-speed tracking accuracy for 2 m telescope. Firstly, frequency characteristic curve of system structure was identified; secondly, a structure filter was designed according to frequency characteristic curve of the system so as to reduce the resonant amplitudes caused by structural mode; then, according to the requirements of the system control performance index, the position controller and feed forward controller were designed to improve the system position tracking performance; lastly, a low-speed control experiment on the telescope turntable was conducted based on the designed hardware platform. The experiment result shows that the telescope is in better stableness and its tracking error RMS is 0.006 1″ when it tracks a slope 0.36″/s position curve, which achieves an extremely low-speed tracking effect; the maximum error value guided by the sine curve is 0.3″ and the tracking error RMS is 0.066″ on the condition of speed 5°/s and acceleration 2°/s2. The experiment result indicates that the design of AC servo control system for 2 m telescope meets the requirements of system tracking accuracy and provides a reference for the design of AC servo control system for large-scale telescope to an extent.