Objective To observe the effect of puerarin on the ICAM-1 gene expression in streptozotocin-Induced diabetic nephropathy rats. Methods Diabetic nephropathy rats were induced by intraperitoneal injection of STZ.Rats were allocated into normal control group,model group,and puerarin group.The puerarin treatment lasted for 16 weeks.During and after the treatment,the general health conditions,blood glucose levels,blood urea nitrogen,serum creatinine,urinary albumin excretion rate of 24-hours,and clearance rate of creatinine of the rats were observed.The ICAM-1mRNA expressions were also determined by in situ hybridization analysis in the kidney tissue of the rats.Results Diabetes mellitus and renal function lesion occurred in the model group and puerarin group.Puerarin could improve the general health of the rats,decrease blood urea nitrogen,serum creatinine,and urinary albumin excretion rate of 24-hours;and increase the clearance rate of creatinine.The ICAM-1mRNA expressions in the kidney were significantly inhibited by puerarin treatment.Conclusion Puerarin has a function of renal protection.