Aim To explore the calcification of renal artery and the activation of BMP2/Smad1/Runx2/Osterix signal pathway in type 2 diabetic nephropathy rats. Methods Forty rats were randomly divided into control group and diabetic nephropathy group (DN group). Type 2 diabetic nephropathy model was established by high sugar and fat diet and streptozotocin (STZ) injection. The calcium content were detected by calcium assay kit in 8,2 and 16 weeks. Calcium depositing in the renal artery was observed by Von Kossa staining. The protein expression of BMP2, Smad1, Runx2 and Osterix were detected with immunohistochemistry. Real-time polymerase chain reaction (RT-PCR) were applied to detect the gene expression levels of BMP2 and Runx2 in the renal artery. Results Contents of blood glucose, blood urea nitrogen(BUN), cystatin C (CysC) and 24 h urinary albumin (24 h UA) of DN group at all time point were much higher than those of control group (P<0.05). Serum creatinine (SCr) of DN group was higher than that of control group since 12th week (P<0.05). The calcium content in DN group were significantly higher than those in control group at each time point (P<0.05). Black granules were found deposited in the renal artery of DN rats in 8 weeks and the black calcium salt was gradually increased with the time passing. No calcium salt was found in control group. Compared with the control group, the protein expression of BMP2/Smad1/Runx2/Osterix signal pathway and the expression of BMP2, Runx2 mRNA in DN group rats were significantly higher. Correlation analysis demonstrated that calcium content was positively correlated with BMP2, Runx2 mRNA(r=0.641, r=0.683,all P<0.01) . Conclusion The renal artery calcification may appear in the early stages of type 2 diabetic nephropathy rats model and the activation of BMP2/Smad1/Runx2/Osterix signal pathway may be an important regulating factor in the renal artery calcification.