The invention provides a joint booster, which consists of a front joint bracket, a front connecting block, a front connecting block localizer, a front joint bracket spring hook holder, a rear connecting block, a rear connecting block localizer, a cambered spring support, a spring anti-slip plate, a rear joint bracket, a rear joint bracket spring hook holder, a tension spring, a belt and a boomer, wherein the boomer consists of a boomer bracket, a rotary rod, a bevel wheel and a bevel claw. According to the booster, the force of joint sports can be increased, and the defect of time and sport force waste on auxiliary exercise due to the fact that conventional exerciser training and joint exercise of people cannot be carried out at the same time can be overcome. Therefore, people can carry out limb action exercise, such as piano playing, typing, running, boxing, gym, medical rehabilitation and other items requiring joint exercise; and when the joint booster is worn, exercise of joint force and flexibility are reinforced in exercise, limb exercise memory of a human body is deepened, and the proficiency level of limb actions is improved.