In my own work, the motion and negative pressure pulse of blast wave in the shock tube are simulated numerically. Based on the formation mechanism of blast wave, the initial operational condition of blast wave is given. A nice hologram is obtained by means of computational fluid imaging, which is useful to make comparision between the numerical results and experimental data. It is found that the negative pressure region is formed after the coefficient wave behind blast wave caught up with the wave head of shock wave. Isodense curve with oval shape is formed due to the influence of nozzle. Numerical results can reflect the operational process of blast wave very well. To this end, a further understanding of the operation and negative pressure phenomenon of blast wave can be obtained, which provides valuable hints for engineering applications.