The main aim of this paper is to study the inelastic deformation of fully clamped rectangular plates under hydrodynamic loading by low rate with drop-hammer, both experimentally and analytically. In the analytic section, some models are presented for predicting the mid-point deflection by two methods consisting the plastic hinge and energy method. in the plastic hinge method, it is assumed that the used plate in the experimental analysis consists a central hinge and four decentralized hinge inside and also four hinges for fully clamed supported conditions; but in the energy method, the proposed model assumes the deformation in three directions and membrane and bending strain, besides the deformation profile and also the strain rate is assumed. To do this, in experimental section, some experiments were conducted on rectangular plates with different thickness, materials and different levels of energy in order to validate the obtained results from analytic results and also surveying the mechanical behavior of materials according to impacts. By comparing analytic and experimental results, it is obvious that results have satisfying accuracy, therefore using the presented analytic models is desired for predicting the mid-point deflection of rectangular plates under the hydrodynamic loading.