Abstract: a telescopic downhole robot was developed, whose control system is the key point that affects its reliability and stability as well. According to the working mechanism of the robot, a novel electro-hydraulic control system was innovated. Further, a numerical simulation model based on electro-hydraulic coupling control was established by comprehensively considering the electric and hydraulic systems, and actuators as well. By analyzing the influence of system fluid rate, traction, and wellbore diameter on the robot kinematics, the movement of the robot under different working parameters was revealed. An experimental scheme of the electro-hydraulic control system was designed, and the influence of the system fluid rate on the motion cycle of the robot was studied. The experimental results show that the simulation curve of the motion cycle of the robot under different system fluid rate is basically consistent with the experimental curve. The research results can provide a theoretical basis for designing and studying hydraulic telescopic downhole robots.