Objective To study the process of stent graft implantation into the aortic dissection model by finite element simulation, calculate the stress distribution at different locations of the aorta after the implantation, and analyze the biomechanical mechanism of new lesions for implantation of stent grafts. Methods Based on the computed tomography angiography (CTA) image data of the aorta, a three-dimensional geometric model of patient-specific aortic dissection was established with image segmentation and reconstruction. The wall thickness and material properties of the aortic dissection of the computational models were set according to the literature data. Stent grafting rings with different geometric parameters were designed in a computer-aided design (CAD) software, and the procedure of stent graft implantation was simulated by a finite element analysis software. Results When the implanted stent graft reached a steady-state, the maximum Von Mises stress of the aorta was markedly related to the position of the stent graft and located at the bare stent or small nickel-titanium alloy ring. In the long-term, this force might cause a new tear to appear at the treated aorta. Conclusions The position of the stent graft had a weak effect on the distribution of the maximum Von Mises stress of the aorta, but there was an obvious effect on the Von Mises stress of the aorta. These research outcomes may provide significant guidance for selecting the position of the stent graft.