Method of inviscid flow field simulation of the outer edge boundary layer for hypersonic vehicle was created, which was faster than the numerical method and more accurate than the engineering method. And the curve of specific heat and the specific heat ratio changed with temperature were matched, which deduced the law of air attribute on different temperatures. Based on the law, the model of parameters of the outer edge boundary layer for hypersonic vehicle was built, and the comparisons of the results of the proposed method and the engineering method as well as the viscid method of blunt double-cone model were analyzed. Result shows that at the 0° angle of attack, compared with the viscid method, the maximum differences of the pressures between engineering method and viscid method are about 1.19% and 2.39% respectively, while at the 10°angle of attack, they are about 5% and 50% respectively. And the proposed inviscid numerical method obtained higher accuracy is superior to the engineering method, which lays the foundation for the thermal environment calculation of hypersonic-glide vehicle.