Abstract: Objective To explore effect of all-inside arthroscopic technique for repairing anterior cruciate ligament(ACL)avulsion fracture of tibial insertion with knotless anchors and high-strength fiber sutures. Methods Eighteen patients with ACL avulsion fracture of tibial insertion were treated with knotless anchor fixation and high-strength technique fiber suture under all-inside arthroscopy. The functional recovery of the knee joints was evaluated by Lysholm score, International Knee Documentation Committee(IKDC)score and Tegner score. The stability and range of motion of the knee were evaluated by Lachman test and knee flexion and extension range of motion(ROM). Results Postoperative follow-up showed that all the fractures healed without postoperative joint infection and failure of internal fixation. Lachman test was negative, and Lysholm score, IKDC score, Tegner score and knee range of motion were significantly better than those before surgery(P< 0.05). Conclusion Knotless anchor fixation and high-strength technique fiber suture under all-inside arthroscopy have significant effects in repairing anterior cruciate ligament avulsion fracture of tibial insertion and they have the advantages of less trauma, strorg fixation, and early knee rehabilitation exercise and so on.