【Objective】 To investigate the serum levels of homocysteine (HCY) and cystatin C (Cys-C) in patients with antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV)associated renal injury, and to explore the diagnostic value of combined detection of HCY and Cys-C in ANCA-associated renal injury. 【Methods】 We selected 70 ANCA-positive patients with renal injury admitted to the Department of Nephrology in our hospital from January 2016 to January 2019. Another 48 patients with ANCA-positive but not complicated with renal injury were in simple ANCA positive group while 50 patients with physical examination who came to the hospital during the same period were in control group. Healthy patients served as the control group. By comparing the differences in the test results of different groups, the area under the curve (AUC) of each test index for ANCA-positive renal injury was determined, and the correlation and diagnostic value of combined detection of HCY and Cys-C for ANCA-related renal injury were calculated. 【Results】 The levels of HCY and Cys-C in the ANCA positive combined with renal injury group, the pure ANCA positive group, and the control group differed significantly (P<0.05). The positive rates of HCY and Cys-C in the two groups were significantly different (P<0.05). The sensitivity and specificity of HCY and Cys-C in combination for the diagnosis of ANCA-positive related renal injury were significantly higher than those of the above indicators alone (P<0.05). ROC curve results showed that HCY combined with Cys-C had a better diagnosis for patients with positive ANCA and associated renal injury and a higher correlation. 【Conclusion】 HCY combined with Cys-C is closely correlated to ANCA-related renal injury, and the combined detection has a positive effect on the diagnosis of patients with ANCA-positive related renal injury, and has guiding value for the treatment of patients.