OBJECTIVE: To study the effect of the Compound of traditional Chinese drugs and Benazepril on gene expression of renal endothelin and its receptor of experimental diabetic nephropathy(DN). To discove the mechanism of the compound of traditional Chinese drugs in treating DN. METHOD: Streptozotocin DN model was built and influenced with the compound of traditional Chinese drugs and Benazepril. The changes of Upro, Glu, HbA1C and (PT-PCR) mRNA expression levels of ET-1, ETA-R of the renal cortex were tested, and thus the histopathological character of the kidney was analysed. RESULT: The compound of traditional Chinese drugs and Benazepril have significant difference from normal saline in the improvement of Upro, Glu, HbA1C. The compound of traditional Chinese drugs have significant difference from Benazepril in the improvement of Glu, HbA1C. The mRNA expression level of ET-1, ETA-R of the renal cortex of DN model was raised. After influenced by the compound of traditional Chinese drugs and Benazepril, the over-expression level de-creased (still higher than normal control ones). The compound of traditional Chinese drugs were more effective than Benazepril to inhibit the proliferation of the stalk region and the third cells. CONCLUSION: ET takes part in the process of diabetic glo-Merulosclerosis. Both the compound of traditional Chinese drugs and Benazepril can influence the expression quantity from the level of gene transcription of ET and its receptor. The compound of traditional Chinese drugs can not only reduce urinary albumin of DN, but also improve blood glucose, glycosylated hemoglubin. And it can inhibit nonenzymatic glucosylation of protein as well as the proliferation of the stalk region and the third cells.