The aerodynamic characteristics of the inflatable reentry decelerator were studied with chemical nonequilibrium numerical simulation using five-species air model. The effects of reentry decelerator′s shape deformation on distributions of flow temperature and pressure , heat flux and pressure along the wall were investigated, and the mole fractions of each species in the flow filed were presented. The modeling results show that the shape deformation of inflatable reentry decelerator has little influence on flow characteristic, and leads an increase of heat flux on the capsule surface. The study of species distribution shows that since N₂ is more difficult to dissociate than O₂, the mole fraction of N is much lower than the mole fraction of O in the flow filed. Under the current calculation conditions, the ration of nitrogen and oxygen along the wall and axis is almost consistent with the incoming flow. The modeling study results are in good agreement with the experiment results, which verify the reliability of the model.