PURPOSE OF THE STUDY To evaluate the therapeutic effects of small incision open reduction and internal fixation and arthroscopic high strength non-absorbable suture on tibial insertion avulsion fracture of the anterior cruciate ligament (ACL). MATERIAL AND METHODS In this prospectively study, 72 patients with ACL tibial insertion avulsion fracture treated from December 2017 to June 2020 were enrolled and divided into group A (treated with small incision open reduction and cannulated screw internal fixation) and group B (treated with arthroscopic high strength non-absorbable suture) using a random number table (n=36). Their general data, surgical indices and incidence of postoperative adverse reactions were compared. Knee function indices were compared before and after treatment, and evaluated by random walk model. RESULTS No significant differences were found in the general data, intraoperative blood loss, preoperative Lysholm score, International Knee Documentation Committee (IKDC) score, Tegner score, knee range of motion and difference of bilateral tibial forward displacement distance, and total incidence rate of postoperative adverse reactions between the two groups (P>0.05). Group B had significantly longer operation time, and significantly shorter hospital stay, time of first ambulation after operation and bone healing time than group A (P<0.05). Both groups had improved Lysholm score, IKDC score, Tegner score and knee range of motion after treatment, especially in group B (P<0.05). The difference of bilateral tibial forward displacement distance significantly reduced in both groups after treatment, particularly in group B (P<0.05). The random walk model revealed that group B had better improvement of knee function than group A. CONCLUSIONS Arthroscopic high strength non-absorbable suture in the treatment of ACL tibial insertion avulsion fracture can dramatically improve the knee function indices of patients, with rapid recovery and high safety, so it has a broad prospect of clinical application. Key words: small incision open reduction and internal fixation, arthroscopic high strength non-absorbable suture, tibial insertion avulsion fracture, anterior cruciate ligament, random walk model.