Objectives: To analyze the value of diagnosis in early renal damage in patients with primary nephrotic syndrome (PNS) by 99mTc-DTPA renal dynamic imaging.Methods: Twenty-one healthy controls (10 men, eleven women; mean age at diagnosis, 32.1±15.3 years; range, 18-63 years) and 24 patients (16 men, eight women; mean age at diagnosis,37.6±19.5 years; range, 14-68 years) with PNS diagnostic criteria underwent 99mTc-DTPA renal dynamic imaging.The PNS patients were divided into two groups: normal serum creatinine (SCr)group of 17 cases; abnormal SCr group of 7 cases.For each case, Gates method to calculate the glomerular filtration rate(GFR) of total kidney, single nephron GFR, the peak time (tp) , half excretion time (t1/2) and the kidney radioactivity counts ratio of 20min with the peak phase (R20/p).Results: (1)There were significant differences between normal people and two groups of PNS in GFR(both P<0.05), the PNS patients GFR have decreased, the group of abnormal SCrGFR decreased more significantly than group of normal SCr(P<0.05).But the single nephron GFR had no difference between left kidney and right kidney(P>0.05).(2) The levels of tp, t1/2, R20/p in normal SCr group (4.09 ± 1.41, 23.08 ± 10.37, 63 ± 11%) and abnormal SCr group (5.97 ± 1.75,25.23 ± 8.86, 79 ± 9%) both had significant differences compared with healthy controls (3.40±0.98, 10.08±13.2,48±10.P<0.05).There was also difference between the two groups of PNS,the worse for the group of abnormal SCr.Conclusions: For patients of PNS with normal SCr, the 99mTc-DTPA renal dynamic imaging of the indicators have been abnormal.Comprehensive analysis of 99mTc-DTPA renal dynamic imaging in patients with primary nephrotic syndrome could evaluate the function of single renal excretion and filtration earlier and effectively detected acute renal failure patients.