Abstract： Objective： To observe the curative effect of therapy of Jiangtang Yishen Prescription combined with western medicine on type 2 diabetic nephropathy and its effect on the endothelial function and hemorheology. Methods： A total of 100 patients with type 2 diabetic nephropathy were randomly divided into the control group and the observation group according to the random number table method， with 50 cases in each group. The control group was given routine treatment， and the observation group was additionally treated with Jiangtang Yishen Prescription based on the treatment of the control group. The clinical effects，endothelial function and hemorheology were compared before and after treatment between the two groups. Results： Before treatment， there was no significant difference being found in the comparisons of levels of fasting blood glucose (FBG)， 2- hour postprandial blood glucose (P2hBG) and glycosylated hemoglobin (HbA1c) between the two groups (P＞0.05)；after treatment，the levels of FBG， P2hBG and HbA1c in both groups were decreased (P＜0.05)，and the above three levels in the observation group were lower than those in the control group (P＜0.05). Before treatment， there was no significant difference being found in the comparisons of levels of 24- hour urinary protein content (24hPRO)， microalbuminuria (mAIb)，β2- microglobulin (β2- MG) and cystatin C (CysC) between the two groups (P＞ 0.05)；after treatment，the levels of 24hPRO，mAIb，β2-MG and CsyC in both groups were decreased (P＜0.05)，and the above four levels in the observation group were lower than those in the control group (P＜0.05). Before treatment，there was no significant difference being found in the comparisons of levels of serum nitric oxide (NO) and endothelin-1 (ET-1) between the two groups (P＞0.05)；after treatment，the serum NO levels in both groups were increased (P＜0.05) and the ET-1 levels in both were decreased (P＜ 0.05)；the serum NO level in the observation group was higher than that in the control group (P＜0.05) and the ET- 1 level was lower than that in the control group (P＜0.05) . Before treatment， there was no significant difference being found in the comparisons of levels of whole blood high- shear viscosity (ηbH)， whole blood middle-shear viscosity (ηbM)，whole blood low-shear viscosity (ηbL)，plasma viscosity (ηp) and fibrinogen (FIB) between the two groups (P＞0.05)；after treatment，the levels of ηbH，ηbM，ηbL， ηp and FIB in the two groups were decreased (P＜0.05)，and the above five levels in the observation group were lower than those in the control group (P＜0.05). Conclusion： Jiangtang Yishen Prescription has a significant effect on controlling the glucose level，reducing proteinuria and protecting the kidney function of patients with type 2 diabetic nephropathy，whose mechanism may be related to effective regulation of the vascular endothelial function， protection of vascular endothelium， improvement of hemorheology and decrease in high blood viscosity.