In order to help patients with lower extremity dyskinesia to perform rehabilitation training, a control of a lower limb exoskeleton rehabilitation robot based on a disc motor is proposed. According to the Lagrangian method, an exoskeleton robot dynamics model is established, the un-modeled part of the system and the total external disturbance are estimated using the extended state observer, and it is eliminated by active disturbance rejection control (ADRC), and it is verified by Matlab simulation experiments. Simulation results show that compared with the traditional PID control, ADRC tracking is stable and has better anti-interference ability, and the tracking error is smaller.