The Hyperloop system is a new concept transportation with high speed in the nearly vacuumed pressure tube. When analyzing the Hyperloop system, aerodynamic drag is a very important parameter due to high velocity. It is known that aerodynamic drag is a function of pressure, shape of the train, blockage ratio, and velocity. Of these factors, this paper focuses on how the velocity of the train affects the flow near the train as well as aerodynamic drag with fixing other factors. Using numerical simulation, it is observed that what value of the velocity begin to generate the shock wave and where the shock wave happens. And this paper also includes reasonable doubt about the assumption that under mach number 0.3, it is proper to use incompressible flow in numerical simulation.