Objective To introduce arthroscopic "internal splinting" repair technique (arthroscopic locking loop stitch with knotless anchor suture-bridge technique) for treatment of acute Achilles tendon rupture and report the 2-year preliminary clinical outcomes. Methods From June 2018 to January 2019, nineteen patients with acute closed Achilles tendon rupture were treated with arthroscopic "internal splinting" repair technique and follow-up more than 2 years. Under arthroscopic monitoring, 2# high-intensity sutures were used to suture the medial and lateral proximal of the Achilles tendon stump. The ends of the sutures were guided to both sides of the calcaneal tuberosity through the deep surface of the Achilles tendon. The ends of the sutures were fixed using 4.5 mm knotless anchor, the sutures were gradually tightened and fixed after the Achilles tendon stump was well aligned using B-ultrasound monitoring. Results All 19 patients completed the operation successfully. No gastrocnemius nerve injury, infection or re-rupture was observed. One patient removed the anchor because of irritation at the medial knotless anchor. At the last follow-up, the average AOFAS score was 96.11 ± 5.02, the average ATRS score was 96.89 ± 4.17, and the average VAS score was 0.39 ± 0.50. All patients returned to their pre-injury exercise level at 6 months after surgery. MRI showed that the injuried tendons restored continuity. Conclusion Arthroscopic “internal splinting” repair technique is a reliable and effective treatment for acute closed Achilles tendon rupture.