Eight weeks old db/db mice were treated with or without rhein at a dosage of 150 mg/kg for 12 weeks. Kidney's total RNA was extracted and renal gene expression profiles were tested using the gene chip GM-U74A from Affymetrix company. Among the total 12 437 tested genes, 1 085 genes were down-regulated and 37 genes were up-regulated in untreated db/db mice when compared with normal control. Among them, 166 genes were down-regulated and 29 genes up-regulated more than 2 fold. It was found that 384 genes were down-regulated and 155 genes up-regulated in rhein treated db/db mice as compared with untreated db/db mice. About 47 genes were down-regulated and 30 genes up-regulated more than 2 fold. Then, an EST, which was down-regulated by about 2 fold in db/db mice and recover to normal level in rhein treated mice, was further analyzed by bioinformatical method and proved to be part of “REKEN cDNA 0610006H10” gene, which function is unknown. After its expression level was further proved by RT-PCR, diabetic nephropathy relative gene,“REKEN cDNA 0610006H10” gene, was cloned for further study.