Objective? To explore the application value of renal function serology in the early diagnosis of diabetic nephropathy. Methods? A total of 142 diabetes patients admitted to Guilin People's Hospital from March 2018 to April 2020 were selected，they were divided into group A（diabetic nephropathy）and group B（nondiabetic nephropathy），with 71 patients in each group，and another 71 healthy individuals from the same period were selected as group C to observe the serological indicators of renal function in three groups. Results? The levels of β2-MG，Cys-C，SCr and BUN in group A were higher than those in group B and C（P＜0.05）. There was no significant difference in the levels of β2-MG，Cys-C，SCr and BUN in group B and C（P＞0.05）. Conclusion? Serum indexes of renal function can be used as the basis for early diagnosis of diabetic nephropath.