Abstract: The traditional Pi controller in the permanent magnet direct drive control system of the outer rotor of the coal mine belt conveyor is easy to be affected by the external disturbance, in this paper, the speed ring is improved by introducing the speed and q-axis current into the active disturbance rejection controller （ADRC） ,the torque observer of sliding mode load and linear ADRC are designed to observe the disturbance of random load and make corresponding compensation for i_q^* . In order to simulate the actual working condition, the control strategy is simulated and analyzed with MATLAB/Simulink under the condition of random load. The results show that the improved control strategy can make the belt conveyor realize good “S” type start characteristic, compared with PI control, PI control can restrain the overshoot of motor speed, reduce the influence of random load change on speed and torque ripple, and improve the stability and reliability of belt conveyor under complex working conditions.