Objective To investigate the effect of fibrocytes and chemokine recepter 7(CCR7) on the process of renal fibrosis induced by adriamycin in rats. Methods Male Sprague-Dawley (SD) 8 weeks old rats (n=52) were divided into two groups randomly, normal control group (CG, n= 20) and model group (MG, n=32). MG rats were injected with 4 mg/kg of adriamycin via tail vein on the first day of the 1st and 2nd week, respectively, while CG rats received 0.9% sodium chloride solution injection of equal volume at the same time. The urine and serum samples were measured at the end of 4, 7, 10 and 13 weeks after the first administration of adriamycin to observe biochemical changes, while the renal tissue of rats was obtained to evaluate renal histological and ultrastructural changes by glomerulosclerosis index and tubulointerstitial index, and to analyze the expression of CD45, collagen I and CCR7 by immunohistochemistry. Results Compared with CG, levels of 24 h urine protein excretion rate (mg, 568±102 vs 21±6, P＜0.01), serum cholesterol (CHO, mmol/L, 6.79±1.47 vs 1.29±0.27, P＜0.01) and triglyceride (TG, mmol/L, 2.57±1.19 vs 0.76±0.11, P＜0.01) increased significantly, whereas serum albumin (Alb, g/L, 21.41±2.11 vs 34.64±0.96, P＜0.01）decreased significantly in the 7th week in MG. The proliferation of mesangial cells, the accumulation of the extracellular matrix and atrophyin or extension of renal tubules in MG were more remarkable than those in CG. There were some cells which expressed CD45 and collagen I simultaneously in the serial sections of renal tissue and renal cortical interstitium in MG. Interstitial infiltration of CD45+ or CCR7+ cells appeared in the 4th week, reached a maximum in the 7th week (P<0.01) and gradually decreased afterward. Conclusions Fibrocytes may be involved in the earlier stage of kidney fibrosis. The immigration of this population from peripheral blood to renal lesion site is possible to be associated with CCR7 protein.