The study is a multicenter, three-arm, open-label, randomized, parallel-controlled trail, which plans to enroll 306 participants diagnosed with acute type A aortic dissection (ATAAD) from 7 hospitals in China. All patients receive total arch replacement (TAR) combined with frozen elephant trunk (FET) implantation and are randomized to Group 1 (arch-clamping technique under mild hypothermia), Group 2 (arch-clamping technique under moderate hypothermia) and Group 3 (Sun's procedure using bilateral antegrade cerebral perfusion) in the ratio of 1:1:1. After a 1-year follow-up, the validity and safety of the mild hypothermic arch-clamping technique for ATAAD was evaluated via the incidence of major adverse events including death, renal replacement therapy, stroke, and paraplegia, as well as times of circulatory arrest, cardiopulmonary bypass, and mechanical ventilation, and length of stay.