Disclosed herein is an orthopedic knee joint brace, which permits smooth knee exercise, increases the durability of a spring, and ensures structural rigidity in a shock absorbing operation. To this end, the orthopedic knee joint brace includes an upper cuff assembly (100) having an anatomical shape of a thigh to support the thigh, and a lower cuff assembly (200) provided under the upper cuff assembly and spaced apart from the upper cuff assembly. The orthopedic knee joint brace includes a pair of damping pivot assemblies (300) coupling facing ends of both sides of the upper and lower cuff assemblies to each other. Each of the damping pivot assemblies has a multiple pivot link structure and a guide damping structure to correspond to the movement of the knee joint.