Abstract: A two-year-old female Cathrow dog, not neutered, fully immunized, weight 37 kg, overweight, and the left rear limb suddenly claudication 1 day before the doctor visit. In order to diagnose and treat the dog, X-ray, palpation of knee joint and anterior drawer test were used for diagnosis. The results showed that the dog was diagnosed with anterior cruciate ligament rupture of the left rear limb, and the tibial plateau level osteotomy（TPLO） therapy was used for treatment after comprehensive judgment, and the prognosis was good. It showed that TPLO therapy had a good effect in the treatment of canine anterior cruciate ligament rupture cases, and it was worth promoting.