Design of retaining wall needs the complete knowledge of earth pressures for both active and passive conditions. Under earthquake condition, the design requires special attention to reduce the devastating effect of this natural hazard. But under seismic condition, the available literatures mostly give the pseudo-static analytical value of the earth pressures as an approximate solution to the real dynamic nature of the complex problem. In the present work, a recently developed pseudodynamic method, which incorporates time dependent effect of applied earthquake load and effect of shear and primary waves, is applied to study effect of variation of parameters like soil friction angle, wall friction angle, time period of earthquake ground motion, seismic shear and primary wave velocities of backfill soil and seismic peak horizontal and vertical ground accelerations on the seismic earth pressures. Again a complete analysis between these two design methodologies shows that the time dependent non-linear behaviour of the pressure distribution obtained in the pseudodynamic method results more realistic design values of earth pressures under earthquake condition.