Objective To analyze the value of diagnosis and differential diagnosis of dynamic renal scintigraphy via observation on renal size,imaging,uptake of tracer agent and functional parameters in acute and chronic renal failure.Methods Ten patients with acute renal failure and fifteen patients with chronic renal failure were confirmed using clinical and biochemical analyse,all patients underwent 99 Tc m-EC and 99 Tc m-DTPA dynamic renal scintigraphy. Two groups functional imaging were analyzed separately,then counted out kidney and aorta mean counts specific value (K/A),kidney uptake high peak value (KP),kidney size (Area),effective renal plasma flow(ERPF),glomerular filtration rate(GFR).Results There was significant difference among above parameters in two groups (P