OBJECTIVE： To investigate the effects of Kangfuxin liquid on repairing cartilage defect model of knee osteoarthritis （KOA） in rabbits and its mechanism. METHODS： Totally 72 male New Zealand rabbits were selected and randomly divided into model control group and Kangfuxin low-dose， medium-dose， high-dose groups， with 18 rabbits in each group. A cartilage defect model of the medial femoral condyle of the right knee joint in rabbits was established by drilling after anesthesia surgery. Then the rabbits in each group were given medicine via articular cavity immediately. Kangfuxin low-dose， middle-dose and high-dose groups were given 20％， 40％， 80％ Kangfuxin liquid； model control group was given constant volume of normal saline consecutively， 0.2 mL/kg， once every 3 days. At 4th， 8th， 12th week after medication， the wound repair of cartilage defect in rabbits was observed. Immediately after medication and at 4th， 8th， 12th week after medication， repaired tissue of cartilage defect in rabbits was scored histologically with Wakitani scoring standard under light microscope. At 12th week after medication， pathological changes of repaired tissue of cartilage defect in rabbits were observed by Masson staining. The levels of NO， SOD and LPO in joint fluid and PYD in urine of rabbits were detected by ELISA. RESULTS： At 4th， 8th， 12th week after medication， compared with model control group， cartilage defects in rabbits were repaired well in Kangfuxin low-dose， medium-dose and high-dose groups. At 4th， 8th， 12th week after medication， compared with immediately after medication and model control group at same time point， histomorphological score of repairing cartilage defect of knee joint in rabbits decreased significantly in Kangfuxin low-dose， medium-dose and high-dose groups （P＜0.05）. At 12th week after medication， compared with model control group， the histopathology degree of cartilage defect of knee joint in rabbits was significantly alleviated in Kangfuxin low-dose， medium-dose and high-dose groups. At 4th， 8th， 12th week after medication， compared with model control group， the levels of NO and LPO in joint fluid and PYD level in urine were decreased to different extent in Kangfuxin low-dose， medium-dose and high-dose groups， while SOD level was increased to different extent； at 12th week after medication， the difference of each index has statistical significance （P＜0.05 or P＜0.01）. CONCLUSIONS： Kangangxin liquid can significantly repair cartilage defect of KOA cartilage defect model rabbits， the mechanism of which may be associated with increasing the expression of SOD and mediating NO-inhibited chondrocyte apoptosis.