Objective To investigate the clinical characteristics and prognosis of antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis with acute kidney injury (AKI) as the first manifestation, and provide new ideas for the prevention and treatment of this disease. Methods A retrospective analysis was performed on 144 patients diagnosed with ANCA-associated vasculitis in Affiliated Hospital of Southwest Medical University between August 2013 and March 2020. The patients were divided into AKI group and non-AKI group according to whether they were complicated with AKI at admission, and the differences in clinical characteristics were analyzed. The risk factors were screened by multiple logistic regression analysis. Results Among the 144 patients with ANCA-associated vasculitis, 30 cases (20.8%) were complicated with AKI at admission, and 70 cases (48.6%) died by the end of follow-up. There were 16 death cases (53.3%) in the AKI group, and 54 death cases (47.4%) in the non-AKI group, but the difference was not statistically significant (P>0.05). Single-factor analyses showed that in the AKI group, the pre-admission incidence of hematuria, neutrophil count, serum creatinine, systolic blood pressure, and Birmingham Vasculitis Activity Score were higher than those in the non-AKI group, while the red blood cell count and estimated glomerular filtration rate (eGFR) were lower than those in the non-AKI group, and the differences were statistically significant (P<0.05). Multiple logistic regression analysis showed that the neutrophil count [odds ratio (OR)=1.172, 95% confidence interval (CI) (1.003, 1.371), P=0.046] and eGFR [OR=0.942, 95%CI (0.907, 0.979), P=0.002] were independent influencing factors for AKI. Conclusions Elevated neutrophil count is an independent risk factor for ANCA-associated vasculitis complicated with AKI. It has certain guiding significance for clinical work. Early identification and intervention of these patients may contribute to reduce the case fatality rate and improve prognosis.