Today, to reduce the cost and increase the safety, test devices like conic shock tube have been widely used to investigate the underwater explosion phenomenon and its impact on structures. A shock tube is designed, manufactured and utilized in the mechanic of explosion laboratory of mechanic faculty of K.N. Toosi University of Technology to study the effect of isotropic metal plates' material in ... [Show full abstract] the present study. The source which creates shock in the utilized shock tube is an explosive material and the positive point is that in such a tube a high pressure is produced with a tiny explosive charge. In order to investigate the effect of the material and the geometry of the utilized metal plate, three materials are considered with two different thicknesses in the experimental tests. The behavior of the plate can be measured if the amount of the pressure produced by the explosive charge and the amount of plate's transformation is specified. To present a semi-experimental equation of the behavior of the plate which is under the explosion loading with the water interface in the experimental tests, numerical simulation is performed with LS-Dyna software. At the end, by combining the experimental and simulation results, the effect of the material and the thickness changes is studied specifically and an explosive charge is provided by adding weight parameter to anticipate the transformation of these metal plates.