Objective To investigate the short-term effectiveness of one-stage anterior cruciate ligament (ACL), posterior cruciate ligament (PCL), and posterolateral complex (PLC) reconstruction combined with medial collateral ligament repair for KD-Ⅳ knee dislocation. Methods Between January 2018 and June 2020, 9 patients with KD-Ⅳ knee dislocation were treated. Of 9 cases, 7 were male and 2 were female with an average age of 32.3 years (range, 23-43 years). The knee dislocation was caused by falling from height in 6 cases and traffic accident in 3 cases. The injury located at left knee in 2 cases and right knee in 7 cases. The time from injury to operation was 14-24 days, with an average of 19 days. The preoperative International Knee Joint Documentation Committee (IKDC) score was 45.6±4.2, Lysholm score was 42.4±7.0, and the knee joint active flexion range of motion was (75.2±12.3)°. The posterior drawer test, pivot-shift test, Dial test, and 0° valgus stress test were all positive. Under arthroscopy, PCL was reconstructed with the autologous tendons, ACL with allogeneic Achilles tendon, PLC with the allogeneic anterior tibial tendon by Larson enhanced reconstruction method, and MCL was repaired with anchor or simple suture. Results The operation time was 2-3 hours (mean, 2.5 hours). All incisions healed by first intention after operation. All patients were followed up12-25 months (mean, 16.1 months). After operation, 2 cases developed knee flexion disorder and pain, and 1 case had knee joint stiffness. At last follow-up, the IKDC score was 76.9±7.4, the Lysholm score was 81.6±6.4, and the knee active flexion range of motion was (122.9±7.2)°, all of which significantly improved when compared with preoperative ones (P<0.05). During follow-up, there was no failure of the grafts. At last follow-up, there were significant differences in the posterior drawer test, pivot-shift test, Dial test, and 0° valgus stress test between pre- and post-operation (P<0.05). The imaging review showed that the positions of the bone tunnels were satisfactory, the reconstructed ACL, PCL, and PLC structures were continuous, and MCL insertions were restored. Conclusion One-stage ACL, PCL, and PLC reconstruction combined with MCL repair to treat KD-Ⅳ knee dislocation can effectively restore knee joint stability, improve joint laxity, and improve joint movement.