Objective To analyze the distribution and risk factors of subgingival flora in oral peri-implantitis. Methods A total of 100 patients who underwent oral implantation surgery in our hospital from May 2021 to May 2022 were selected. While, 28 patients with peri-implantitis (inflammation group) and 72 patients without peri-implantitis (non-inflammation group) were followed up for 1 year. The subgingival microorganisms were detected, and the in?uencing factors of peri-implantitis were analyzed by single factor and binary Logistic regression analysis. Results After determination, 45 strains of bacteria were detected in 28 patients (34 implants) in the in?ammation group, and the top three were anaerobic bacteria (66.67%), oral streptococcus (46.67%) and aerobic bacteria (24.44%). Binary Logistic regression analysis showed that diabetes, drinking, smoking, chronic periodontitis and poor alveolar bone around the implant were independent risk factors for peri-implantitis (OR>1, P<0.05); binder residue and oral hygiene habits were protective factors for peri-implantitis (OR<1, P<0.05). Conclusion The subgingival ?ora of oral periimplantitis is mainly anaerobic bacteria and oral streptococcus, and the in?uencing factors are mostly objective reasons. E?ective health guidance for patients after oral implantation surgery is conducive to reducing the incidence of implant in?ammation.