Rainfall is one of the most common reasons for mechanically stabilized earth wall failure in various places of the world. The most common mode of failure was a circular type global slope failure. Rainfall-induced retaining wall instability is widespread in tropical regions. The numerical analysis was carried out to gain insight into the total infiltration process, with a special emphasis on the hydraulic behavior of wall with different backfill materials like sand, marginal soil and flyash; the behaviour of wall is analyzed, and results are compared. The purpose of this study is to ascertain how the external and internal stability of the wall affects the change in pore water pressure caused by rainwater infiltration into the wall. SEEP/W was used to perform a transient seepage analysis with the application of rainfall on the surface of wall as a flux boundary condition. The SLOPE/W was used to check the stability of the wall and SIGMA/W for the lateral deformation. As water flux increases from 9 to 180 mm/hour, the stability of wall decreased. During heavy rainfall condition, the stability of wall decreases because water cannot dissipate and lateral earth pressure increases and lateral displacement is higher. It was also observed that as the length of the reinforcement and the angle of internal friction increases, its stability also increases significantly.