Objective:To construct and validate a predictive model for the risk of excessive blood loss in pa-tients with ruptured tubal pregnancy,and to provide a basis and tool for the assessment of changes in the condi-tion of patients with ruptured tubal pregnancy.Methods:Clinical data of inpatients with ruptured tubal pregnancy from January 2014 to July 2021 were retrospectively analyzed,who underwent surgical treatment in the Depart-ment of Gynecology,Dongguan Maternal and Child Health Hospital.The pelvic blood volume was categorized into excessive blood loss and non-excessive blood loss groups based on whether the amount of pelvic blood was found to be≥750 ml intraoperatively.Factors influencing the occurrence of excessive blood loss were screened and modeled by univariate analysis,Lasso regression,and multi-factor Logistic stepwise regression.The area un-der the subject working characteristic curve(AUC)was used to evaluate the discrimination of the predictive mod-el,the model's consistency was evaluated by calibration curve and goodness-of-fit test,and the clinical utility of the model was evaluated and validated by the decision analysis curve.Finally,column line plots were drawn.Results:①A total of 386 patients with ruptured tubal pregnancy were included,of whom 124(32.12%)had blood loss≥750 ml.②The optimal predictors for predicting concomitant blood loss in patients with ruptured tubal preg-nancy were screened,including:days of abdominal pain,dizziness,pallor,fatigue,the maximum diameter of para-metrial mass,human chorionic gonadotropin(β-hCG),and hemoglobin(Hb)and the model and the column line graphswere constructed accordingly.③The prediction model AUC was 0.827(95%CI 0.781-0.873);the cut-off value was 0.391,at which point the specificity and sensitivity were 68.55%and 84.35%,respectively,and the AUC validated within the model by resampling was 0.804.Clinical decision curves showed that the threshold probability intervals for the maximum net benefit values ranged from 8.5%-97%,respectively.Conclusions:The constructed prediction model was validated to suggest good discriminatory efficacy and degree of consistency.As a tool,it has clinical application value in predicting the risk of hemorrhage in patients with ruptured tubal pregnan-cy.It can help to determine the occurrence of adverse events such as hemorrhagic shock at an early stage and improve the success rate of rescue treatment.