The differences between frozen shoulder and rotator cuff injury are as follows: 1. Clinical manifestations, frozen shoulder mainly shows pain around the shoulder and limited activity, while rotator cuff injury has limited active activity, but not passive activity; 2. Disease causes, generally rotator cuff injury is associated with a history of trauma or a history of repetitive shoulder joint activity, while frozen shoulder rarely shows trauma; 3. Frozen shoulder, aggravated by cold, while rotator cuff injury is not affected; 4. MRI, edema and adhesions around the shoulder joint in frozen shoulder, while rotator cuff injury mostly suggests tearing or edema around the supraspinatus tendon and rotator cuff; 5. Pain, rotator cuff injury has especially intense pain at night, while frozen shoulder has more consistent pain around the day and night.