In this study, the nonlinear dynamic response of basalt/nickel FGM composite plates has been investigated under blast load. Homogenous Laminated Model (HLM) and Power-Law Model (PLM) are used to model the basalt/nickel FGM composite plates. von Kármán large deflection theory of thin plates are considered for the geometric nonlinearity effects. The equations of motion for the plate are derived by the use of the virtual work principle. Approximate solutions are assumed for the space domain and substituted into the equations of motion. Then the Galerkin Method is used to obtain the nonlinear differential equations in the time domain. The Finite Difference method is applied to solve the system of coupled nonlinear equations. The effects of two different approximations in order to model the basalt/nickel FGM composite plates have been investigated and the results are discussed.