Abstract: In order to assist limbs to perform the standardized and intensive rehabilitation training, a 4-DOF wearable robot for upper limbs rehabilitation based on exoskeleton is developed. The rehabilitation robot can realize the vertical outreach/adduction, horizontal up/down motion, and the supination/pronation motion of the shoulder and the flexion/extension motion of the elbow. Firstly, each joint's motion angle of the human arm is identified according to the rehabilitation medicine, and the structure of the rehabilitation robot is designed under the principle of minimum driving moment. Then, the kinematics and dynamics simulation is carried out to analyze the structure, and the structural optimization is completed accordingly. Finally, the control system is designed for the continuous passive mode in the recovery motion. The experiment result shows that the structure is convenient to wear, degrees of freedom of the robot's motion are coaxial to that of the human upper limbs' motion, it can support and draw each part of the affected arms effectively, and traction force can be applied to each joint of the upper limbs accurately.