Abstract: This paper reports a case of disseminated intravascular coagulation (DIC) that occurred early after hybrid surgery for type B aortic dissection with an aortic arch aneurysm. Through analyzing the clinical manifestations, imaging findings, and treatment response of the patient, we propose that massive false-lumen thrombosis may serve as a critical trigger for early postoperative coagulation activation leading to DIC. Corresponding treatment strategies are suggested to enhance clinicians’ ability to recognize and manage this critical condition.