The utility model provides a novel knee joint traction device. Including a guide plate, the guide plate is connected with the lower end of the shank supporting plate; the upper end of the shank supporting plate is connected with the shank telescopic cylinder movable end. The fixed end of the shank telescopic cylinder is connected with the lower end of the movable joint; the upper end of the movable joint is connected with the fixed end of the thigh telescopic cylinder; the movable end of the thigh telescopic cylinder is connected with a thigh supporting plate; a shank sheath is arranged on theshank supporting plate; thigh sheaths are arranged on the thigh supporting plates; the shank sheath binds the shank supporting plate to the shank of the patient through the shank fixing belt; the thigh support plate is fixed on the thigh of the patient by the thigh sheath through the thigh fixing belt; the lower limb traction device is simple in structure and convenient to operate, lower limb traction is conducted through the shank telescopic cylinder and the thigh telescopic cylinder, traction force can be finely adjusted, a better traction treatment effect is achieved, practicability is high, and the lower limb traction device can be used in a hospital rehabilitation center or a family and has good market popularization prospects.