Background Mortality and complications remain high after Acute Type A Aortic Dissection (ATAAD) open surgery, which is associated with coagulation dysfunction. Platelets play an important role in the process of coagulation. This study was to explore the relationship between postoperative platelet counts and postoperative mortality in patients with ATAAD after open aortic repair surgery.Methods Patients with ATAAD who underwent Total Arch Replacement and Frozen Elephant Trunk in Fuwai Hospital from 2011 to 2015 were selected in this study. The perioperative data were collected and sorted through the electronic clinical case system. Multivariate Logistic regression was used to analyze the risk factors for death within three years after surgery.Results A total of 495 patients were included in the analysis. After correction with the confounding factors, postoperative platelets count remained as an independent factor that was associated with lower mortality (OR = 0.918, 95%CI 0.853-0.988, P = 0.023).Conclusions The study indicated that decreased postoperative platelet count may lead to increased mortality, in patients with ATAAD underwent open aortic repair surgery.