Spasticity is a velocity-dependent stretch reflex disorder of the body motor system developing after the injury of the central nervous system, in which certain muscles are continuously contracted involuntarily. Conventional methods such as the modified Ashworth scale, Spasm frequency scale, pendulum test and isokinetic dynamometer had some disadvantages: limitation in discriminating the increase of resistance, immovable and expensive device, not enough study parameters. Therefore, it is necessary to introduce clinically more useful instrument, which can produce objective data and are more convenient on spasticity measurement. Spasticity measuring methods were reviewed and a new measuring instrument was designed and introduced. The new measuring system is a portable spasticity-measurement system, which encompass various scopes of spasticity-related human signals such as electrophysiologic, kinematic and biomechanical data. Our device was designed in order to measure the joint angle, angular velocity, electromyographic signals and force. We suggest that this new system can diagnose the spasticity of the muscles, objectively.