To explore the value of thrombin markers in predicting coronary artery thrombus load in elderly patients with acute ST segment elevation myocardial infarction (STEMI). Methods A total of 142 elderly patients with STEMI treated in our hospital from July 2020 to July 2021 were selected and divided into low thrombus load group (n=88) and high thrombus load group (n=54). The clinical data of the two groups were compared, the factors affecting the high coronary thrombus load were analyzed by multivariate Logistic regression, and the back propagation (BP) neural network model was constructed, the receiver operating characteristic (ROC) curve was used to analyze the discrimination of thrombin markers and the model to predict the coronary artery thrombus load, and the calibration curve was used to evaluate the accuracy of the model prediction. According to the optimal critical value of thrombin markers obtained by ROC curve, the patients were divided into group A, group B and group C, the 1-year survival rates of the three groups were compared by Kaplan-Meier method. Results The results of multivariate Logistic regression analysis showed that the elevated levels of cardiac troponin I (cTnI), C-reactive protein (CRP), lipoprotein phospholipase A2 (Lp-PLA2), D-dimer (D-D), plasmin-antiplasmin complex (PAP), thrombomodulin (TM) and tissue-type plasminogen activator-inhibitor-1 complex (t-PAIC) were risk factors for high coronary artery thrombus load, the prolongation of activated partial thromboplastin time (aPTT) was a protective factor (P＜0.05). The areas under the ROC curve of aPTT, D-D, PAP, TM, t-PAIC and their combination are 0.808, 0.795, 0.817, 0.718, 0.755 and 0.866, respectively. The differentiation degree and accuracy of the BP neural network model are better. The 1-year survival rate in group A (aPTT≤25.96 s, D-D≥0.82 mg/L, PAP≥2.13 μg/L, TM≥37.49 ng/L, t-PAIC≥7.12 ng/mL, n=29) was significantly lower than that in group B (aPTT＞25.96 s, D-D＜0.82 mg/L, PAP＜2.13 μg/mg/L, TM＜37.49 ng/L, t-PAIC＜7.12 ng/mL, n=48) and group C (the remaining patients, n=65) (P＜0.05). Conclusion aPTT, D-D, PAP, TM, t-PAIC are closely related to high coronary thrombus burden and prognosis in patients with acute STEMI