Abstract: As the position and shape of human intestinal canal are unfixed for reason of the relative floating property of canal, a compliant control method for colonoscopy robots based on force sensing is proposed to improve the safety and reliability of the endoscopy. Firstly, the force sensor mounted on the colonoscopy robot is analyzed and designed according to the robot surface structure. Then, a compliant control algorithm is proposed based on the analyses on biomechanical characteristics of the intestinal canal and the coupling relationship between the robot joints. Finally, a robot control system is built to verify the feasibility of the algorithm by experiment. And experimental results show that the colonoscopy robot's ability to sense the contact pressure on intestinal canal is improved with the proposed method, which ensures the pressure value is within the threshold, and thus the security and reliability of the intestinal inspection are improved.