Objective To explore the predictive value of thromboelastography (TEG) parameters and antineutrophil cytoplasmic antibody (ANCA) for adverse pregnancy outcomes in patients with early⁃onset severe preeclampsia (EOSP). Methods A total of 98 patients with EOSP were selected as the research subjects, all of whom underwent TEG examination and ANCA level measurement. Based on the occurrence of adverse perinatal pregnancy outcomes, 98 EOSP patients were divided into favorable outcome group or adverse outcome group. General data, TEG parameters, and ANCA positive rate were compared between the two groups. Multivariate Logistic regression model was used to identify factors influencing adverse pregnancy outcomes in EOSP patients. Receiver operating characteristic (ROC) curves were plotted to analyze the predictive value of TEG parameters and ANCA positive rate for adverse pregnancy outcomes in EOSP patients. Results A total of 36 EOSP patients experienced adverse pregnancy outcomes, with an incidence rate of 36.7%. Compared with the favorable outcome group, the adverse outcome group exhibited shorter reaction time (R) and a lower coagulation index (CI), while higher maximum amplitude (MA), ANCA positive rate, systolic blood pressure, diastolic blood pressure, 24⁃hour urinary total protein (24h UTP) content, as well as total cholesterol, LDL⁃C, and HDL⁃C levels (P<0.05). Multivariate Logistic regression analysis revealed that increased R was a protective factor for adverse pregnancy outcomes in EOSP patients, whereas increased MA, ANCA positive, and elevated 24h UPT content were the risk factors for adverse pregnancy outcomes in EOSP patients (P<0.05). ROC curve analysis demonstrated that the sensitivities of R, MA, ANCA positive for alone and jointly predicting adverse pregnancy outcomes in EOSP patients were 77.80%, 75.00%, 72.20%, and 83.30%, respectively, with specificities of 79.00%, 66.10%, 75.80%, and 88.70%, respectively. The area under the curve (AUC) for each was 0.788, 0.765, 0.740, and 0.896, respectively (P<0.05). The AUC for the combined prediction was greater than that for any single indicator (P<0.05). Conclusion Some abnormal parameter (e.g. R, MA), and ANCA positive are correlated with adverse pregnancy outcomes in EOSP patients. These indicators as abovementioned possess certain predictive performance for such outcomes, and their combination offers superior predictive performance.