In this paper, the effect of a relativistically intense Gaussian laser pulse, on the propagation of electron plasma wave is studied. The nonlinear effects considered here are the relativistic decrease of the plasma frequency and the ponderomotive expelling of the electrons. Modified coupled equations for laser and electron plasma wave are derived from fluid equations. These coupled equations are solved analytically and numerically to study the laser intensity in the plasma and the variation of amplitude of the excited electron plasma wave. It is seen that the effect of including the ponderomotive nonlinearity is significant on the excitation of plasma wave. This should affect the number of energetic electrons and their energy range on account of wave particle interaction.