Abstract: Objective: To analyze the renal plasma flow of 1 356 chronic nephritis patients,so as to educe the relationship of the duration, clinical type and kidney function of chronic nephritis patients to their renal plasma flow.Methods: Check on the patients with isotope renogram.Results: The longer the patients′ duration,the lower the renal plasma flow;No obvious difference appeared in renal plasma flow for two groups of patients which had nephropathy or had normal kidney function（P＞0.05）.The renal plasma flow of chronic nephritis patients with hypertension and common type was more lower than that of patients with normal kidney function（P＜0.01）;Obvious difference appeared in renal plasma flow for comparing chronic nephritis patients who had normal kidney function with the patients in compensatory phase or in lose compensatory phase（P＜0.05）.Conclusion: The value of renal plasma flow may reflect the extent of damage of kidney function.