Measurements of underwater explosion parameters and their effects are still the major problem for naval designer. In this study, thermo-chemical calculations have been carried out using EXPLO5 code to determine the underwater explosion parameters for different selected explosive mixtures. Preparation of the different types of explosive mixtures based on melt cast explosive (TNT) and plastic bonded explosives (PBXs) based on polyurethane binder system were presented. The effect of different aluminum weight percentage for the selected explosive mixture has been investigated with respect to the impulse and the resulted deformation. Underwater experimental measurements of the prepared explosive mixtures based on steel plate's deformation were determined and compared. It was concluded that PBX based on RDX in addition to 25 wt% aluminum and 30wt% ammonium perchlorate produces the highest underwater explosion performance from all the tested samples. This explosive mixture is candidate to replace the traditional well known TNT in the underwater explosive applications.