The purpose of functional exercise of the upper limb after breast cancer surgery is to restore the function of the affected side. After breast cancer surgery, because of the large flap separation and lymph node dissection in the axilla, the upper limb movement is usually restricted, which may cause poor reflux. Therefore, in the early stage, functional exercise will be performed to a small extent in order to reduce the possibility of lymphedema and venous thrombosis in the upper extremity. In the later stage, as the drainage fluid decreases and the drainage tube is removed, full functional exercise of the upper extremity should be performed. The range of motion should be gradually increased, including the shoulder joint in addition to the wrist and elbow joints, and the arm should be lifted, laterally lifted, extended forward and backward, and even rotated in a comprehensive manner to ensure that it does not become disabled.