Objective: To study the application value of 3.0T MRI 3D-MERGE sequence in evaluating the degree of supraspinatus tendon injury. Methods: A total of 52 patients with shoulder pain diagnosed with arthroscopy were enrolled. The 3.0T MRI 3D-MERGE sequence and conventional sequences (including T1WI, T2WI-FS, T2WI-FS on axial plane and PDWI-FS on oblique sagittal plane) were performed, and the results were retrospectively analyzed. According to the arthroscopic findings, the patients were divided into 4 groups: group Ⅰ(without supraspinatus tendon injury), group Ⅱ(mild tear of supraspinatus tendon, <50%), group Ⅲ (moderate to severe tear of supraspinatus tendon, ≥50% but not completely) and group Ⅳ(supraspinatus tendon tear completely). The diagnostic efficacy of 3D-MERGE sequence, conventional sequences alone and combination for supraspinatus tendon injury were compared. Results: The diagnostic efficacy between 3D-MERGE sequence, conventional sequences alone and combination for differentiating supraspinatus tendon with tear from without tear were similar (all P values>0.05). The sensitivity,specificity,positive predictive value,negative predictive value of the 3D-MERGE sequence, the conventional sequences and the combined two sequences were 100%, 80.00%, 88.90%, 100%, and 65.60%, 100%, 100%, 64.50%, and 100%, 90.00%, 94.10%, 100%, respectively. However, for evaluating supraspinatus tendon tear≥50% and above, the diagnostic efficacies of the 3D-MERGE sequence and the combined two sequences were better than that of conventional sequences (both P values<0.05). There was no significant difference between the 3D-MERGE sequence and the combined two sequences (P=0.38). Conclusions: Compared with conventional sequences, 3D-MERGE sequence has a higher performance for diagnosing supraspinatus tendon injury from moderate to severe degree or above, and it could be used as a supplementary sequence for evaluating the degree of supraspinatus tendon injury.