Abstract：A lightweight compliant robotic arm with 3DOF is designed to make the robot arm have better position tracking performance and human-robot interaction security. Using carbon fiber material to achieve lightweight,a series elastic actuator (SEA) is designed to realize the structural compliance of the robotic arm. The kinematic model and dynamic model are set up for the lightweight compliant 3DOF robotic arm. The work space of the robotic arm is computed based on its kinematic model.The position control experiment of the robotic arm is designed. The position and pose of the robotic arm are obtained by the MTI position sensor, and MTI position errors correction is proposed. By comparing the following performance of the joints of the robotic arm and MTI position,the position following error of the joint 1,2,3 are 7%, 5%, 2%, and the maximum position errors on X, Y, and Z are 19.25%, 14.43%, 6.4%.The results show that the robotic arm reaches a good position tracking performance in free workspace.