Abstract: Objective To research the mechanism that curcumin inhibits sodium nitroprusside (SNP) -induced apoptosis of chondrocytes in rats. Methods The carilage cells were obtained from articular cartilages of SD rats (4 rats in each group). The cartilage cells were divided into control group (A), the SNP injured group (B), SNP+5 μmol/L curcumin group(C), SNP+10 μmol/L curcumin group (D), SNP+ 20 μmol/L curcumin group(E), and SNP+ 30 μmol/L curcumin group (F). The effects of different concentrations of curcumin on the proliferation of chondrocytes and the activity of chondrocytes in each group were detected by CCK8 method. The expression of MMP-13, caspase-3, Bax and Bcl-2 genes in chondrocytes were detected by RtPCR. The nuclear apoptosis of chondrocytes were detected by Hoechst 33342 staining. Western blotting technique was used to detect the expression of mitochondrial apoptosis pathway-associated protein. Results ① The 20 μmol/L curcumin had the most proliferative effect on chondrocytes. ② The cells activity by CCK8 assay: group A＞group E＞ group D＞group C＞group F＞group B. ③In group C, D, E and F, the expression of caspase-3, Bax and Bcl-2 in chondrocytes was significantly different from group A and B. ④Hoechst 33342 staining showed that curcumin inhibit SNP-induced chondrocyte nuclear chromatin damage and reduce mitochondrial membrane potential in chondrocytes. ⑤The caspase-3 and Bax protein expression of chondrocyte by Western blotting: group B＞group E＞group A; The Bcl-2 protein expression of chondrocyte by Western blotting: group A＞group E＞group B. Conclusion The curcumin can prevent SNP-induced rat chondrocyte apoptosis via inhibition of mitochondria-dependent pathway.