In order to study gas dynamic resonance performance of coaxial injector, high precision and high resolution NND scheme was used to solve Reynolds averaged Navier-Stokes equations. Numerical simulation was used to study process of oscillatory flow in different coaxial injector-resonance tube system. Flow field structure and character were obtained. It is obvious that coaxial injector and circle injector have similar resonance heating rules and flow field character. And resonance heating temperature decrease in every resonance cycle when the areas of coaxial injector reduce. The coaxial injector-s distance range between injector and resonance tube where intense resonance will occur is shorter than that of circle injector, and inlet pressure range of coaxial injector is wider than that of circle injector.