Objective,2,To observe the therapeutic effect of Yucan Granules （YCG） on diabetic nephropathy （DN） mice and explore its mechanism.,Methods,2,Eighty SPF male C57 mice were randomly divided into normal group and model group. Ten mice in the normal group were fed with normal diet， and 70 mice in the model group were fed with high-fat and high-sugar diet combined with intraperitoneal injection of streptozotocin （STZ） to establish the model of DN mice. Among them， 50 mice were successfully molded and randomly divided into model group， losartan potassium group （losartan potassium 10 mg/kg） and YCG low， medium and high dose groups （YCG 1.5，3，6 g/kg） with 10 mice in each group. The treatment groups were given corresponding drug by gavage， and the normal group and model group were gavaged with 0.9% sodium chloride solution by mass fraction， once a day. After continuous administration for 4 weeks： ①The general state of mice was observed， and the changes of body mass of mice before and after administration were compared. Fasting blood glucose （FBG） was measured after administration. ②The pathological changes of renal tissue were observed by hematoxylin-eosin （HE） staining， fuchsin-aniline blue （Masson） staining and PAS staining. ③The ultrastructural changes of glomerular podocytes were observed by transmission electron microscope. ④The expressions of nephrin， a podocyte marker protein and nephroblastoma gene 1 （WT1） protein were detected by immunohistochemistry and Western blot.,Results,2,①Compared with the normal group， the general state of the model group mice was poor， with a decrease in body mass and an increase in FBG （,P,<,0.05）； Compared with the model group， the state of mice in each treatment group improved， their body mass increased， and their FBG decreased. There was a statistically significant difference in FBG between the medium and high dose groups of YCG （,P,<,0.05）. ②HE， Masson and PAS staining showed that compared with the normal group， the renal tubule wall of the model group became thinner， the lumen dilated， the inflammatory cells infiltrated， the renal interstitial fibrous tissue proliferated. Compared with the model group， the wall of renal tubule became thinner， the lumen dilated， the proliferation of fibrous tissue decreased， the infiltration of inflammatory cells decreased in the YCG groups. ③Transmission electron microscopy observations showed that： compared with the normal group， the foot processes of glomerular podocytes in the model group merged with each other and some foot processes disappeared； Compared with the model group， the fusion and disappearance of podocytes in the YCG groups were obviously improved， and the improvement effect of podocyte damage in the YCG medium and high dose groups was obvious. ④The results of immunohistochemical staining and Western blot showed that compared with the normal group， the expression of Nephrin and WT1 proteins in the renal tissue was significantly decreased in the model group （,P,<,0.05）； Compared with the model group， the expression of Nephrin and WT1 proteins in the renal tissue was significantly increased in the YCG groups （,P,<,0.05）.,Conclusion,2,YCG can treat DN by reducing the level of blood glucose in DN mice and infiltrations of the inflammatory cells in renal tissue， and protecting damaged podocyte.