Objective To provide histological evidence for clinic tendon reconstruction on severe medial collateral ligament injury in rabbits. Methods Medial collateral ligaments of two knee joints were completely incised to create own control model of MCL rupture. The operation group intimated the procedure of human being MCL reconstruction with semitendinous tendon. In the 4th,12th,16th,24th weeks, healing of MCL was observed by anatomy and the picrosirius-polarization method. Results In the 4th week, the MCL healing tissue of ex-periment group is more than control group. The average ratios of type Ⅲ collagen to Ⅰ, Ⅲ collagen in the experiment group [(0.263±0.075), (0.235±0.041), (0.210±0.045), (0.197±0.029)] were significantly lower than those in control group [(0.310±0.072), (0.286±0.045), (0.261±0.046), (0.236±0.043) ] in the 4th, 12th, 16th, 24th weeks, respectively (P < 0.05). Conclusions The semitendinons tendon reconstruction can improve MCL healing in early and middle period after injury.