The multi-joint isokinetic training and testing system refers to a system that can maintain a constant movement speed and variable resistance during joint movement. The movement speed is pre-set on the machine. During the test, muscle force only increases muscle strength and torque output without changing the angular velocity during the movement. That is, the movement speed is constant, and the muscles can generate maximum muscle force at any point in the entire movement process. It is a multifunctional device for evaluating muscle function and training muscle strength.