Objective:To observe the effects of Danggui Buxue Decoction on the expressions of activating transcription factor 6 (ATF6),C/EBP homologous protein (CHOP) and cysteinyl aspartate specific proteinase-3 (Caspase-3) in the renal tissue of diabetic nephropathy rats,and discuss its mechanism of protecting kidney. Methods60 male SD rats were randomly divided into the control group and modeling group. The model of diabetic nephropathy(DN)was established in the modeling group by streptozotocin (STZ) with intravenous injection in tail combined with the high fat and high glucose diet. After successful modeling,the rats were randomly divided into the model group,gliclazide group,Danggui Buxue Decoction groups with high- and low-dose,10 rats in each group. The gliclazide group was treated with gliclazide sustained-release tablets at a dose of 2.68 mg·kg-1·d-1. The Danggui Buxue Decoction groups with high- and low-dose were treated with Danggui Buxue Decoction at doses of 7.14 mg·kg-1·d-1 and 1.78 mg·kg-1·d-1,respectively. The control group and the model group were treated with equivalent 0.9% NaCl solution. After administration for continuous 8 weeks,the protein and mRNA expression levels of ATF6,CHOP and Caspase-3 were detected by Western blot and PCR. The apoptosis rate of positive cells in renal tissue of rats in each group was detected by TUNEL staining.  Results:Compared with the control group,the mRNA and protein expressions of ATF6,CHOP and Caspase-3 were up-regulated in the model group and the rate of TUNEL positive cells was increased (P<0.01). Compared with the model group,the mRNA and protein expressions of ATF6,CHOP and Caspase-3 were down-regulated in the gliclazide group and Danggui Buxue Decoction groups with high- and low-dose,and the rate of TUNEL positive cells was significantly decreased (P<0.01). The mRNA and protein expressions of ATF6,CHOP and Caspase-3 and the rate of TUNEL positive cells in the Danggui Buxue Decoction group with high-dose were significantly lower than those in the gliclazide group or low-dose group (P<0.01).  Conclusion:Danggui Buxue Decoction can reduce the renal cell apoptosis in diabetic nephropathy rats. Its mechanism may be related to the down-regulation of ATF6,CHOP and Caspase-3 and the inhibition on endoplasmic reticulum stress.