Abstract: Objective To investigate the dynamic changes of renal pathological morphology in the rat model with 5/6 nephrectomy. Methods Observed by light and electron microscope. Results The characteristics of renal dynamic changes of 5/6 nephrectomy rat：glomenrulus enlarged ,mesangial cells hyperplasia and tubule expansion at 2 weeks. At 8 weeks, mesangial cells severe hyperplasia and tubule-interstitial inflammation and expansion.At 12 weeks,focal segmental glomerular sclerosis and renal interstitial fibrosis. At the last of 40 weeks, we could see most of glomerulus fibrosis and sclerosis and tubule-interstitial severe fibrosis. Conclusion The changes of 5/6 nephrectomy in rats were accorded with renal fibrosis in human, it was a ideal model to research in chronic renal failure and renal interstitial fibrosis.