Abstract: To explore the effects of Cynanchum paniculatum paeonol on apoptosis of articular chondrocyte and the expression of Bcl-2 and Bax in rabbits with knee osteoarthritis(OA), the rabbit model was established by anterior cruciate ligament transaction and excision of partial medial meniscus. From the first week after the OA model established, Cynanchum paniculatum paeonol, triamcinolone acetonide and 0. 9% saline were injected in the right knee with 0. 2, 0. 2 and 0. 3 mg, respectively, twice a week for 5 weeks. Articular cartilage samples were taken and sliced one week after the end of treatment. The morphological changes of cells were observed under electronic microscope; the TUNEL method was employed to observe the apoptosis of articular chondrocyte; and the immunofluorescence assay was used to detect theexpression of Bcl-2 and Bax inchondrocytes. The results showed that the apoptosis rates in Cynanchum paniculatum paeonol group and triamcinolone acetonide group were significantly lower than that of the control group(P< 0. 05, P< 0. 01). Cynanchum paniculatum paeonol and triamcinolone acetonide could increase the expression of Bcl-2 and decrease the expression of Bax, thus raising the ratio of Bcl-2/Bax and inhibiting apoptosis, and the Bcl-2/Bax ratio in Cynanchum paniculatum paeonol group was much higher than that of model group(P< 0. 01).