Subacromial impingement syndrome can be diagnosed by the following aspects: First, clinical symptoms. Clinical symptoms may include shoulder pain and limitation of shoulder joint movement, especially pain during shoulder abduction, and limitation of movement. Secondly, on physical examination, there can be pain in the shoulder joint during internal and external rotation of the shoulder joint, and there can be a fixed pressure point under the shoulder peak, which should be considered as subacromial impingement syndrome. Third, according to the patient’s age, most subacromial impingement syndrome is caused by degeneration in the elderly and is commonly seen in middle-aged and elderly people. Fourthly, if the patient is diagnosed with subacromial impingement syndrome, it should be treated early.