CPM belongs to a kind of passive joint training and rehabilitation machine used in rehabilitation therapy, patients need to be rehabilitated after limb injury or limb surgery, the rehabilitation method includes support, manipulation or rehabilitation physiotherapy, and at the same time with the machine exercise, known as the CPM machine, CPM machine for the simulation of the human body’s normal rehabilitation and exercise process, at the same time adjusted according to the individual, to enable inactivated joints in the adjustment of reasonable parameters to passive activities to help the joint recovery. The CPM machine conforms to the principle of human joint activity, and can be adjusted to different conditions and micro-environments to simulate the human body in the rehabilitation of the required joint activity force and working range. CPM is more powerful than the normal manipulation, joint activity, and belongs to the state of continuous activity, which can be continuously adjusted and regulated in the process of limb rehabilitation and exercise in order to determine the patient’s recovery situation after the operation. CPM must be used under the guidance of a physician, and is a machine that is adjusted according to the different parts of the injured part and the required range of joint movement and stage of activity, which has positive therapeutic significance and therapeutic value for the patient’s limb function rehabilitation and later treatment.