Objective To observe the effect of Xiaozhong decoction on apoptosis of chondrocytes and the number of isogenous groups of rabbits for animal model of osteoarthritis. Methods Thirty-six seven-month-old New Zealand rabbits with the weight of 2.6-3.2 kg， female in half， were made for animal models of osteoarthritis. All rabbits were equally randomized into six groups， model group， blank group（the same volume of normal saline）， contrast group（saline dissolved with glucosamine tablets）， low-concentration decoction group（40g/kg）， middle-concentration decoction group（80g/kg） and high-concentration decoction group（160g/kg）. All rabbits were medicated by gavage at 4g·kg-1·d-1. After gastric gavage for 28 days， cartilage of knee of rabbits were taken to observe by optical microscope. The number of isogenous groups was counted in every light microscopic view. The apoptosis of chondrocytes of rabbits for animal models of osteoarthritis was checked by TUNEL， the percent of BCL-2 positive chondrocytes was checked by immunohistochemical method. Results There was excessive apoptosis of chondrocytes in animal models of osteoarthritis， meanwhile isogenous groups and the percent of BCL-2 positive cells was declined. Xiaozhong decoction could inhibit the apoptosis of chondrocytes and raise the number of isogenous groups and the percent of BCL-2 positive chondrocytes. 1. The number of isogenous groups declined in model group while increased with decoction concentration from low turned middle after treated 4 weeks， and the differences between the two groups were significant. The differences of high-concentration decoction group from 4 weeks to 8 weeks was insignificant， while the number of isogenous groups of all other groups rose as time went on the differences between all other groups were significant. 2. AI declined after treated by Xiaozhong decoction， especially， AI declined much more with decoction concentration rose. The differences among the decoction groups were significant. AI of blank group rose significantly after 12 weeks， however， AI of model group and contrast group rose significantly in 8 weeks， rose insignificant beyond 8 weeks. AI declined treated by Xiaozhong decoction as time went-on from 4 weeks to 8 weeks and 12 weeks， the differences among three periods were significant. 3. The percent of BCL-2 positive chondrocytes of model group was lowest among all groups. It rose gradually with decoction concentration from low turned middle to high， and the differences among the decoction groups were significant. It rose gradually as time went-on from 4 weeks to 8 weeks and 12 weeks， and the differences among three periods of all groups were significant. Conclusions Xiaozhong decoction could inhibit the apoptosis of chondrocytes and exert effect on up-regulating the number of isogenous groups and the percent of BCL-2 positive chondrocytes of rabbits for animal models of osteoarthritis.