With the development of the society, Cheer aerobics develop rapidly and also get many companies’ attention. In order to let the ordinary people learn the Cheer aerobics well in a healthy and scientific way, this passage has carried on studying the High kick of Cheer aerobics, and get the moment of inertia when the Cheer aerobics athletes high kick, what’s more, we also find out the velocity relationship of athletes’ legs and hips, knees and ankles according to analyzing the Dynamics. And get to know the potential energy and kinetic energy will be produced when the Cheer aerobics athlete’s high kick, that is to say the athletes can effectively increase the momentum of knee joint by the braking of the hip joint. Similarly the athletes braking the momentum of knee joint and transfer it to ankle joint again to accelerate the ankle joint. So that we get the conclusion that it is more helpful to accelerate the knee joint if the calf of the angular velocity is larger than the thigh of the angular velocity and we can also find out that to the accelerate the knee joint, Cheer aerobics athlete’s need to accelerate out speed of calf legs when they high kick to make the calf of the angular velocity is larger than the thigh of the angular velocity. As a result, it may hurt the ankle joint, knee joint as well as thigh because of the high speed of the ankle joint and the short of buffer time. But comparing with the ankle joint, the speed of the knee joint and thigh is small and has a long buffer time so the damage rate can be slightly lower.