Objective　To detect the biomarkers in urine of rats with minimally-changed nephrotic syndrome (MCNS) by optimal surface enhanced laser desorption/ionization time of flight-mass spectrometry (SELDI-TOF-MS).　Methods　Thirty SD rats were randomly divided into normal control group

untreated group and prednisone treatment group. Except for the normal control group

rats were injected with adriamycin (5.5 mg/kg once) via caudal vein to induce MCNS. Ten days later

the rats were administered with prednisone or distilled water

respectively

for 21 d. Urine was collected from rats. Urinary peptide or protein peaks were detected by SELDI-TOF-MS and weak cation exchange protein chip CM10

respectively. Differentially expressed protein and polypeptides were analyzed with Biomarker Wizard Software.　Results　Under optimal experimental conditions

the average variation coefficient for relative peak intensity in control group was 18.0%（7.50%-35.89%）. In different ranges of m/z values

the number of mean peak intensities was 33 in untreated group

which was significantly greater than that in normal control group（P0.05）. Of the 33 mean peak intensities

21 were up-expressed and 12 were down-expressed. The expression level of the 6 differentially expressed proteins was higher in untreated group than in prednisone treatment group (P0.05）with a mean peak intensity similar to that in normal control group.　Conclusion　By optimizing the experimental conditions and controlling quality

SELDI-TOF-MS can be used as a tool to detect potential biomarkers in urine of rats with MCNS. Differentially expressed proteins contribute to the early diagnosis and treatment of MCNS.