Chronic dacryocystitis often leads to a poor prognosis due to factors like chronic inflammation resulting in lacrimal duct obstruction and recurrent infections. Therefore, this study aims to investigate the risk factors of poor prognosis in patients with chronic dacryocystitis treated by endoscopic nasal dacryocystostomy and to establish a risk prediction model. We retrospectively analyzed the clinical data of chronic dacryocystitis patients (n = 101) treated between January 2022 and February 2024. They were divided into a training set (n = 71) and a validation set (n = 30). Patients were followed up for three months post-operation, and recurrence rates were assessed. Logistic regression analysis was used to identify risk factors for poor prognosis, and a nomogram model was developed utilizing these risk factors. Model validation involved the bootstrap method, calibration curves, receiver operator characteristic (ROC) curves, and the Hosmer-Lemeshow test. Out of the 101 patients, 27 (26.73%) experienced recurrence. The older age, longer operation time, and greater intraoperative bleeding were all associated with poor prognosis (all p < 0.05). Multivariate regression indicated that age (odds ratio (OR) = 2.18, 95% CI: 1.30-3.68), operation time (OR = 1.89, 95% confidence interval (CI): 1.13-3.17), and intraoperative bleeding (OR = 1.69, 95% CI: 1.06-2.69) were significant risk factors. The nomogram model incorporating these factors showed an area under the curve (AUC) of 0.666 for the training set and 0.585 for the validation set. Furthermore, for the training set, sensitivity and specificity were 0.654 and 0.621, and for the validation set, they were 0.598 and 0.548, respectively, with calibration curves indicating good agreement. Age, operation time, and intraoperative bleeding are significant factors affecting the prognosis of patients with chronic dacryocystitis.