Abstract:[Objective] To investigate the clinical outcome of arthroscopic 270° capsular release in the treatment of frozen shoulder.[Methods] A retrospective study was conducted on 36 patients who received arthroscopic 270° capsular release for primary frozen shoulderin our hospital from January 2019 to July 2021. The clinical documentations were evaluated. [Results] All patients had operation performedsuccessfully, with no complications of vascular and nerve injury occurred during the operation. All patients were followed up for an averageof (17.0±3.6) months. As time elapsed from that before surgery to 1 month, 6 months postoperatively and the latest follow-up, the Chineseshoulder score [(35.1±2.8), (58.4±3.8), (64.2±3.7), (67.4±5.3), P<0.001], Constant-Murley score [(38.2±5.5), (59.1±4.5), (77.4±3.5), (82.8±5.4), P<0.001], forward flexion ROM [(64.1±8.6)°, (111.8±7.8)°, (114.8±9.5)°, (153.6±6.3)°, P<0.001], abduction ROM [(59.3±5.3)°, (110.6±6.0)°, (144.4±6.5)°, (149.2±6.3)°, P<0.001], body side external rotation ROM [(13.6±4.1)°, (29.5±5.9)°, (40.1±5.3)°, (48.8±6.3)°, P<0.001]were significantly improved. [Conclusion] Arthroscopic 270° capsular release for the treatment of primary frozen shoulder does significant-ly relief pain, and effectively improve shoulder joint motion, with satisfactory clinical results.