Aimed at the turntable servo system with large load torque variation and parameter variation, the servo system state equations were established. System model based on nonlinear proportion integration and differential (PID) controller and extended state observer was designed. Output angle, angle velocity and uncertain disturbance of the system were estimated by the observer, meanwhile dynamic modeling state and uncertain disturbance of the estimated system were used to compensate the servo system. The simulation results indicate that tracking precision of turntable servo system is improved by compensation control of this method, and the system has good control effect under condition of large load variation with outside strong disturbance.