Abstract: Currently, the peripheral vascular stents used in interventional medicine are mainly self-expanding nitinol stents, which can autonomously expand at the lesion site to open the narrowed vessel, thereby restoring the normal lumen structure and blood flow. This study employs a phenomenological constitutive model incorporating the temperature and strain as internal variables, along with a user-defined subroutine UMAT, to conduct finite element simulation analysis of a concave-convex auxetic self-expanding stent with negative Poisson’s ratio. The mechanical performance of this stent is compared with that of a traditional V-shaped stent with positive Poisson’s ratio during self-expansion, in term of scaffolding capability, axial positioning stability, and stress-strain distribution. The results indicate that: Both the V-shaped and concave-convex stents successfully achieve self-expansion by leveraging the superelasticity and shape memory effect of nitinol, with the shape memory effect effectively mitigating the residual stress and strain during expansion; When the environmental temperature during self-expansion is the same, the influence of the two material properties of nitinol on the stent’s scaffolding performance is consistent; The axial shortening rate of the stent is primarily influenced by its geometric structure and is independent of the material properties. As the self-expansion proceeds, the V-shaped stent exhibits axial shortening (positive Poisson’s ratio effect), while the concave-convex stent demonstrates axial elongation (negative Poisson’s ratio effect). This study provides an effective theoretical model and simulation approach for the deployment process of nitinol vascular stents utilizing the superelasticity and shape memory effect.