This utility model relates to an aortic arch stent and a thoracic aortic aneurysm endovascular stent implantation device. The aortic arch stent can simultaneously self-expand three small stents, which are guided by the stent delivery system under the guidance of an endoscope into the true lumen of the aortic dissection. The stents are released simultaneously, and after expansion, they form tubular or aortic arch-like structures that can support the true lumen of the blood vessel formed by the dissection without affecting the blood flow in the branches of the aorta. The operation is simple, safe, reliable, and has definite therapeutic effects, making it suitable for use in most hospitals.