The compressibility of the flow field out of the projectile was not considered when the traditional turbulence model was derived. In this paper, the effect of the k-ε turbulence model with compressibility modifications on the aerodynamic simulation was studied using OpenFOAM software. The aerodynamic parameters were computed respectively using the standard k-ε turbulence model and the modified kε turbulence model. After contrasting the results got by the computation method with the ones gained using experiment method, the results calculated by the modified turbulence model were proved to be more precise than the ones computed by the standard k-ε turbulence model. The results gained in this paper show that the compressibility in the flow field out of the projectile cant be ignored and the compressibility modifications can upgrade the precision of computation evidently.