The invention discloses a device for rehabilitating functions of an elbow joint of an upper limb after an operation. The device is characterized by comprising an elbow joint bushing, upper arm bone positioning plates, front arm bone positioning plates, a hinge shaft, a function rehabilitator, a longitudinal connecting fabric strap, a transverse connecting fabric strap, positioning airbags, air tubes and an air valve, wherein at least four upper arm bone positioning plates are fixedly arranged on the outer periphery of the upper half part of the elbow joint bushing; at least four front arm bone positioning plates are fixedly arranged on the outer periphery of the lower half part of the elbow joint bushing; the function rehabilitator is arranged on the lateral surface of the elbow joint bushing; and the positioning airbags are arranged between the upper arm bone positioning plates and the elbow joint bushing as well as between the front arm bone positioning plates and the elbow joint bushing respectively, and are communicated with the air valve through the air tubes. Due to the adoption of the structure, the device has the advantages of novel structure, simplicity in use, convenience for operation, high function rehabilitation speed, active exercises, combination of fixation and rehabilitation, and the like.