The subacromial joint, also known as the second shoulder joint, consists of the acromion, rostral process, and rostral shoulder ligament forming the rostral shoulder arch. Between the rostral shoulder arch and the greater tuberosity of the humerus there is a subacromial bursa similar to a joint bursa, below which the supraspinatus tendon and the long head of the biceps tendon pass. Subacromial impingement syndrome is a series of clinical symptoms caused by the narrowing of the subacromial tunnel due to various causes. When the shoulder is lifted or externally rotated, the soft tissue structures of the rotator cuff are squeezed between the acromion and the humeral head and are subjected to repeated, minor impingement and stretching. The subacromial impingement sign can be caused by overapplication of the shoulder, repeated shoulder trauma, and thus tendonitis and bursitis, which increases the space occupied by the subacromial region and leads to friction and impingement of the rostral shoulder arch. In subacromial impingement sign, the subacromial tissues become vasodilated, permeability increases, exudation increases, and normal blood circulation is affected after edema, accelerating tissue swelling and degeneration, leading to dysfunction. According to Neer’s typing, subacromial impingement syndrome can be divided into 3 stages: stage I is characterized by acute bursitis accompanied by subacromial edema and hemorrhage; stage II is characterized by inflammatory reaction of the rotator cuff and local thickening of rotator cuff injury; stage III is characterized by full-layer injury of the rotator cuff. According to the supraspinatus exit slice, the shape of the rotator cuff is divided into three types: type I is flat, type II is curved, and type III is hook-shaped, and it is believed that type III rotator cuff is more prone to subacromial impingement syndrome. The causes of subacromial impingement syndrome can be summarized into the following three aspects: I: primary subacromial impingement syndrome caused by anatomical abnormalities. The anatomical abnormality causes a narrowing of the supraspinatus outlet due to a reduction in the acromion-humeral head spacing, causing the rotator cuff to be squeezed between the humeral head and the rostral arch of the shoulder. Low acromion and anterior subacromial hook deformity are considered to be the most common intrinsic causes of extrusion. In particular, supraspinatus outlet stenosis is the main etiology of subacromial impingement syndrome. Thickened rostral shoulder ligaments, acromioclavicular joint and subacromial tuberosity, and humeral tuberosity may also contribute to bursal and supraspinatus tendon injury. Second: Secondary subacromial impingement syndrome caused by damage to the static and dynamic stabilizing structures from various causes. This is caused by repeated and excessive use of the affected limb, especially when the affected limb exceeds the head movement and workers, due to the collision of the rostral shoulder arch and the acromion when the shoulder joint is abducted and flexed, repeated and minor impact and stretching injuries, resulting in damage to the static and dynamic stability structures, shoulder joint instability, mild upward displacement of the humeral head, secondary impingement, inflammation and degeneration of the rotator cuff, and even tearing. This destabilization, impingement and rotator cuff injury can create a vicious cycle. Those with primary joint laxity are more dependent on power stabilizing structures and can present with symptoms without the above mentioned history. Third: Other signs of impingement resulting from rotator cuff injury, such as primary degenerative rotator cuff lesions and posterior supra-articular glenoid impingement signs. Diclofenac is a non-steroidal anti-inflammatory analgesic, which can inhibit the formation of inflammatory substances and achieve pain relief. The external application of blood-activating herbs and infrared physiotherapy can promote blood circulation in the affected area and accelerate the absorption and dissipation of inflammatory substances to achieve pain relief. Through these comprehensive treatments, we are able to achieve significant effects on stage I and II cases and patients with type I and II acromegaly. For stage III and some stage II cases and type III acromion patients, surgical treatment is required. Subacromial kyphoplasty is performed and part of the rostral shoulder ligament is removed to remove the impingement factor and decompress sufficiently to avoid further impingement after surgery. The principle of subacromial kyphoplasty is to change the shape of the anterior outer 1/3 of the acromion and increase the volume of the subacromial space to remove the impingement factor and restore the normal function of the rotator cuff. There are two types of subacromial plication: open incisional surgery and arthroscopic surgery. With the advancement of research on subacromial impingement syndrome and the development of arthroscopic surgery, arthroscopic subacromial plication and decompression of the shoulder has achieved the same or better results than open surgery. Although arthroscopic subacromial plication is a difficult procedure, it is less invasive, has a wider field of view, does not incise the joint, and preserves the original static structure of the shoulder joint as much as possible, especially the integrity of the second shoulder joint, and preserves the attachment point of the deltoid muscle on the acromion, preserving the power unit of the shoulder joint and facilitating early functional exercises and restoration of function. Through this clinical observation, it can be concluded that the treatment of subacromial impingement syndrome should be treated separately in different cases. Stage I and II cases of subacromial impingement syndrome and patients with type I and II acromion are suitable for the application of a combination therapy based on closure. Stage II and III cases and patients with type II and III acromion are suitable for the application of shoulder arthroscopic acromioplasty. Both treatment methods can achieve good results. Most of them can be treated non-surgically. Chinese medicine can play a great role in this regard.