In order to study the similarity law of explosive shock wave parameters with different orders of magnitude TNT, four static explosion experiments were carried out. At different measure points on the ground, some pressure-time curves of shockwave were got. Meanwhile, some parameters of shockwave were obtained, like peak overpressure, positive pressure time and positive pressure impulse, which were also compared with the data in the literature. The result showed that shockwave's parameters satisfied the explosion similarity law. However, when the scaled distance was less than 3, the statistical law of experimental data was poor. Through fitting quantities of experimental data, the empirical formulas of shockwave's parameters were obtained, which could be applied to the explosion of TNT whose magnitudes vary from several kilogram to several hundred kilogram.