Abstract: Background　Acute pulmonary embolism (APE) has high incidence and mortality. Existing diagnostic methods are invasive or equipment-dependent, making diagnosis difficult in primary and critically ill settings. Objective　To identify independent predictive factors for APE and develop a diagnostic model incorporating readily available clinical indicators. Methods　 A multicenter retrospective case-control study was conducted. Patients with suspected acute pulmonary embolism (APE) who underwent computed tomography pulmonary angiography (CTPA) at the Sixth Medical Center of PLA General Hospital from January 2022 to December 2024 were enrolled as the modeling cohort, From January 2006 to December 2019, the patients who were suspected of having APE and underwent CTPA examination at the First Medical Center of the PLA General Hospital constituted the external validation cohort.. Demographic characteristics, clinical symptoms, medical history, laboratory parameters, and electrocardiographic (ECG) findings were collected. Independent predictors were identified using univariate analysis, least absolute shrinkage and selection operator (LASSO) regression, and multivariable logistic regression, and a diagnostic nomogram was subsequently developed. Model performance was evaluated by receiver operating characteristic (ROC) curve analysis, calibration curves, decision curve analysis (DCA), and internal validation with bootstrap resampling. External validation was performed in the independent cohort, and the model was compared with the Wells score and the Geneva score. Results　A total of 373 patients were included in the modeling cohort (214 APE, 159 non-APE) and 63 patients in the external validation cohort (35 APE, 28 non-APE). In the APE group, there were 112 males and 102 females, with a mean age of 63.9±15.9 years; in the non-APE group, there were 98 males and 61 females, with a mean age of 40 years. Logistic regression analysis showed that D-dimer, history of lower-extremity deep vein thrombosis (DVT), N-terminal pro-B-type natriuretic peptide (NT-proBNP), chest tightness/chest pain, history of pulmonary embolism, prolonged activated partial thromboplastin time (APTT), and T-wave abnormalities on ECG were independently associated with APE (P＜0.05). The predictive probability was modeled as P= eX/(1+eX), where X=0.654×(D-dimer)+ 2.087×(prior DVT)+0.473×(NT-proBNP) + 1.735×(chest tightness/chest pain)+2.263×(prior PE)+0.137×(APTT)+1.172×(T-wave change) -12.483. A nomogram was constructed based on this equation. The area under the ROC curve (AUC) for the model was 0.944 in internal validation and 0.988 in external validation, both outperforming the Wells score (0.733) and the Geneva score (0.841). Conclusion The seven factor nomogram demonstrates excellent diagnostic performance and is easy to use, making it suitable for rapid bedside screening of suspected APE, particularly in critically ill patients and in primary healthcare settings.