Objective:To investigate the clinical characteristics and influencing factors of postoperative epistaxis after endoscopic sinus surgery.S Methods:SA retrospective analysis was conducted on the clinical data of 44 patients who experienced postoperative epistaxis after endoscopic sinus surgery at the First Affiliated Hospital of USTC between June 2020 and June 2025 (experimental group). Additionally, clinical data from 105 patients who did not experience epistaxis during the same period were collected as the control group. The clinical characteristics of postoperative epistaxis were described by analyzing the experimental group. Comparative analysis between the experimental and control groups, along with multivariate logistic regression, was performed to identify the influencing factors of postoperative epistaxis. Results:The highest incidence of postoperative epistasis occurred within the first week after surgery (25.00%). The most common bleeding site was the sphenopalatine artery (38.64%). The highest incidence of bleeding was observed in patients undergoing endoscopic sinus surgery for sinonasal tumors (36.36%). Electrocautery under general anesthesia was the most frequently used hemostatic method (38.64%). The experimental group had a significantly higher proportion of males and a history of anticoagulant use compared to the control group, while the preoperative use of hormones was lower in the experimental group (P < 0.05). Multivariate logistic regression analysis indicated that male gender (95% CI: 1.054 ~ 5.615, P = 0.037) and a history of anticoagulant use (95% CI: 1.167 ~ 109.846, P = 0.036) were independent risk factors for postoperative epistaxis (P < 0.05). Preoperative use of hormones (95% CI: 0.145 ~ 0.839, P = 0.019) was identified as a protective factor (P < 0.05). Conclusion:Postoperative epistaxis after endoscopic sinus surgery most commonly occurs within the first week after surgery. The sphenopalatine artery is the most frequently involved vessel. Surgery for sinonasal tumors carries the highest risk of bleeding. Electrocautery under general anesthesia is the primary treatment method. Male gender and a history of anticoagulant use increase the risk of bleeding, while preoperative use of hormones can reduce the risk.