In this paper, an improved algorithm to measure Chinapsilas EMU spacesuit joint damping parameters for the old passive robot system is presented. The measuring principle is based on robot kinematics and dynamics. Firstly, a kinematic model of the passive robot and the EMU spacesuitpsilas arm is built according to the special mechanical structure. Secondly, improved methods of solving the inverse kinematics of the EMU spacesuit arm including flexible joints are proposed. And finally, a new algorithm that eliminates the gravity effect is implemented to calculate the damping torques of the EMU spacesuit joints. Experimental results and verification on SGI workstation proved the correctness and effectiveness of the proposed measuring method.