Abstract: Objective To investigate the clinical value of natriuretic peptide in tubular injury of type 2 diabetes mellitus. Methods 37 healthy controls，31 type 2 diabetics without nephropathy, 26 patients with pristine diabetic nephropathy and 23 patients with clinical diabetic nephropathy were enrolled in the study and categorized into four groups. C-type natriuretic peptide (CNP) and urodilatin (URO) were measured by radioimmunoassay. The changes of CNP and URO levels among four groups were analyzed, and correlation analyses were performed between natriuretic peptide and urinary micro-albumin/urine creatinine (MA/UCr). The efficiency index of CNP and URO were evaluated by receiver operation characteristic (ROC). Results Compared with those in the diabetics without nephropathy, pristine diabetic nephropathy and clinical diabetic nephropathy，the CNP and URO levels decreased significantly in the course of diabetic nephropathy (P<0.001). The levels CNP were significantly increased in the diabetics without nephropathy compared to controls (P<0.001). The value of CNP and URO were significantly correlated with MA/UCr (P<0.001). In early phase of type 2 diabetes mellitus, the area under curve of CNP and URO were 0.762 and 0.759. When the cut-off values of CNP and URO were ≤10.2 pg/mL and ≤51.5 pg/mL, The sensitivity and specificity were 69.34% and 70.23%, 67.14% and 71.29%, respectively．Furthermore, CNP and URO had similar diagnosis efficiency with MA/UCr. Conclusion The changes of CNP and URO level have clinical value in pristine tubular injury of type 2 diabetes mellitus.