Objective To investigate the correlation between D-dimer level within 2 hours on admission and early in-hospital major adverse events (MAEs) in patients with acute type A aortic dissection undergoing arch replacement and the frozen elephant trunk (FET) implantation. Methods The patients with acute type A aortic dissection undergoing arch replacement and the FET implantation, who hospitalized in our hospital from September 2017 to December 2022, were included in this retrospective study. Grouping based on the occurrence of in-hospital major adverse events (MAEs) after total arch replacement and FET implantation, with no in-hospital MAEs as a control group and in-hospital MAEs as an observation group. The perioperative data were compared between the two groups. Univariate and multivariate analyses were used to investigate the risk factors for MAEs (in-hospital mortality, gastrointestinal bleeding, paraplegia, acute kidney failure, reopening the chest, low cardiac output syndrome, cerebrovascular accident, respiratory insufficiency, multiple organ dysfunctionsyndrome, gastrointestinal bleeding, and severe infection). Receiver operating characteristic (ROC) curve was used to evaluate the predictive value of the prediction area under the ROC curve (AUC). Results Finally 218 patients were collected, including 157 males and 61 females with an average age of 51.54±9.79 years. There were 152 patients in the control group and 66 patients in the observation group. In-hospital mortality was 2.8% (6/218). The level of D-dimer, lactic acid, cardiopulmonary bypass time, aortic cross-clamping time, ventilator-assisted time and ICU stay in the observation group were higher or longer than those in the control group (P=0.013). Multivariate logistic analysis showed that D-dimer (OR=1.077, 95%CI 1.020-1.137, P＜0.05) was an independent risk factor for MAEs in hospital. The level of D-dimer within 2 hours admission predicted that the AUC of MAEs in hospital was 0.83 (95%CI 0.736-0.870, P＜0.05), and the optimal critical point was 2.2 μg/mL, with sensitivity and specificity of 84.8% and 73.0%, respectively. Conclusion Increased D-dimer levels at admission are associated with early in-hospital MAEs in the patients with acute type A aortic dissection undergoing arch replacement and FET. These results may help clinicians optimize the risk evaluation and perioperative clinical management to reduce early adverse events.