Inflammation and glomerular endothelial dysfunction promote diabetic kidney disease (DKD) progression, but the mechanisms are not fully understood. Allograft inflammatory factor-1 (AIF-1) is a protein that regulates inflammatory reactions and immune responses. This study aimed to explore the mechanism of AIF-1 in a DKD animal model and mouse renal glomerular endothelial cells (MRGECs). We injected AIF-1-shRNA into the tail vein to knockdown AIF-1 in db/db mice. Metabolic index, renal pathological changes and inflammatory factors were measured in each group. Lentiviral transfection was used to overexpress AIF-1 in MRGECs. Inflammatory factors, oxidative stress and nuclear factor-κB (NF-κB) pathway-related proteins were examined. AIF-1 expression was upregulated in glomerular endothelial cells in renal tissues of db/db mice. Knockdown of AIF-1 reversed kidney injury and renal inflammation in db/db mice. In a 30 mM high-glucose environment, overexpression of AIF-1 in MRGECs activated the NF-κB pathway and induced inflammation and oxidative stress. Moreover, this damage could be attenuated by the addition of an NF-κB inhibitor (BAY 11-7082). In conclusion, AIF-1 facilitates glomerular endothelial cell inflammation and oxidative stress in DKD via the NF-κB signaling pathway. Our results provide evidence for the molecular mechanism of DKD and may offer a potential target for DKD treatment.