To explore surgical reconstruction therapy and clinical effect of serious medial collateral ligament ruptures of the knee.Thirty-three patients with medial collateral ligament rupture were treated by operative repair and reconstruction. The degree of injury in all patients was Grade III. Some patients complicated with posterior medial capsule and anterior cruciate ligament, complete posterior cruciate ligament rupture, and some complicated with menisci injury, even tibial plateau fracture. After repairing the anatomical structure of medial collateral ligaments, we liberated organic semitendinous tendon or bone-patella tendon-bone, and reconstructed superficial medial collateral ligament.Thirty-three patients were followed up for 43.1(3 approximately 71) months. After the operation, conditions were improved obviously. Instability and pain of knee released in 27 patients, 5 patients felt pain, and 4 patients still had dysfunction of knee flexion and extension. Stress X-ray showed that: 1 patient's knee joint space widened over 5 mm. According to Lysholm scoring system, the postoperative score was significantly higher than the preoperative score (P<0.01).Medial collateral ligament reconstruction based on repairing the anatomical structure is effective and satisfactory. Autologous bone-patella tendon-bone or semitendinous tendon is a good choice for medial collateral ligament reconstruction.