Objective To evaluate the effectiveness and feasibility of a transverse small incision intrathecal “loop” minimally invasive suture for acute Achilles tendon rupture. Methods The clinical data of 30 patients with acute Achilles tendon rupture treated with transverse small incision intrathecal “loop” minimally invasive suture between January 2022 and October 2023 was retrospectively analyzed. The patients were all male, aged from 29 to 51 years, with an average of 39.8 years. The cause of injury was acute sports injury, and the time from injury to operation was 1-14 days, with an average of 3.4 days. The operation time, incision length, intraoperative blood loss, intraoperative complications, wound healing, and hospital stay were recorded. Postoperative appearance and function of ankle were evaluated by American Orthopaedic Foot and Ankle Society (AOFAS) ankle-hindfoot score, Vancouver Scar Scale (VSS) score, and Arner-Lindholm score. Results The operation time ranged from 30 to 90 minutes, with an average of 54.2 minutes; the incision length ranged from 1.3 to 3.5 cm, with an average of 2.2 cm; the intraoperative blood loss ranged from 5 to 70 mL, with an average of 22.3 mL; and the hospital stay ranged from 2 to 6 days, with an average of 3.7 days. All incisions healed by first intention, and there was no incision infection, poor healing, and deep venous thrombosis. All patients were followed up 5.3-22.0 months (mean, 14.7 months). During the follow-up, all the 30 patients had returned to exercise, and there was no complication such as Achilles tendon re-rupture, postoperative infection, and gastrocnemius muscle injury. At last follow-up, the AOFAS ankle-hindfoot score was 82-100, with an average of 95.1; the VSS score was 1-4, with an average of 2.1; according to the Arner-Lindholm score, 24 cases were rated as excellent and 6 cases as good. Conclusion Transverse small incision intrathecal “loop” minimally invasive suture for the treatment of acute Achilles tendon rupture has the advantages of simple instrument, convenient operation, small trauma, quick recovery, and satisfactory effectiveness.