s: To reduce the quality of the hemiplegia rehabilitation exoskeleton robot, a kind of auxiliary lower limb exoskeleton robot was designed. It utilizes a cable driven knee joint, which has the advantages of simple structure and light quality characteristics. Also use Adams to establish the dynamic model of the exoskeleton joint, rope module established soft cable driven model, by Ariel biological motion analysis software, hip, knee and ankle joint motion data acquisition and simulation analysis is carried out by using spline function. Through the simulation analysis soft cable driven in the step motion process in different spring pre tightening force and spring stiffness on transmission characteristics and driving torque and provide the basis for further research and design of lower extremity exoskeleton.