Abstract: ［Abstract］Objective To investigate the changes of urinary β2-microglobulin （β2-MG）， retinol conjugated protein （RBP）， N-acetyl-beta-D nucleosidase amino acids （NAG） and serum cystatin C （Cys C） in patients with primary nephrotic syndrome （PNS）， and explore the application value of those indexes in PNS diagnosis. Methods　Fifty-three patients with PNS from Sep. 2009 to Sep. 2015 were enrolled in this study， and 40 healthy people were selected as the control group. The levels of β2-MG， RBP， NAG in urinary and Cys C in serum were measured in two groups， and the receiver operator characteristic curves （ROC） were drawn out for investigating the diagnostic value of four indexes to PNS. Results The levels of β2-MG， RBP， NAG in urinary and Cys C in serum of patients with PNS were significantly higher than control group （P＜0.01）. The RBP， NAG and Cys C had the higher efficiency in diagnosis PNS than β2-MG， the differences were statistically significant （P＜0.05）. There were no significant differences in diagnosis PNS between RBP， NAG and Cys C （P＞0.05）. The area of RBP under the ROC curve was 0.897（95%CI was 0.807-0.987）bigger than NAG， Cys C and β2-MG. Conclusion β2-MG， RBP， NAG in urinary and Cys C in serum have high sensitivity and specificity in diagnosis PNS， monitoring the levels of β2-MG，RBP，NAG in urinary and Cys C in serum may be helpful for diagnosis and clinical therapy of PNS.