Abstract： Objective To analyze the risk factors for lymphovascular space invasion(LVSI)in patients with low-grade endometrial carcinoma,construct a nomogram prediction model,and evaluate its effectiveness.Methods The clinical data of 167 patients with low-grade endometrial carcinoma who underwent initial treatment in the Department of Gynecology,Beijing Friendship Hospital,Capital Medical University from January 2015 to May 2023 were retrospectively analyzed.The patients were divided into non-vascular invasion group(143 cases)and vascular invasion group(24 cases)according to vascular invasion.Logistic regression analysis was used to determine the risk factors of LVSI in low-grade endometrial carcinoma.A nomogram model for predicting the risk of LVSI in low-grade endometrial carcinoma was established,and the consistency coefficient and calibration curve were used to evaluate the predictive performance and conformity of the model.Results Multivariate Logistic regression model(stepwise selection method)was used to analyze the independent risk factors of LVSI in patients with low-grade endometrial carcinoma.The results showed that long vaginal bleeding time,triglycerides 1.7 mmol/L,carbohydrate antigen 125 ≥35 kU/L,International Federation of Gynecology and Obstetrics clinical stage Ⅱ and above were independent risk factors for LVSI in patients with low-grade endometrial carcinoma(odds ratios=1.000,1.070,1.820,7.700,all P＜0.05).The independent risk factors screened by multivariate Logistic regression analysis were used to establish a nomogram model for predicting the risk of LVSI in low-grade endometrial carcinoma.After calibration and verification,the predicted risk was close to the actual risk,and the concordance index was 0.843.Conclusion Clinical high staging,serum high triglycerides,high carbohydrate antigen 125,and long preoperative vaginal bleeding time are risk factors for LVSI in patients with low-grade endometrial carcinoma.The nomogram model based on these indicators can be used to evaluate the risk of LVSI in these patients before surgery.