The collapse of earth walls reinforced by geosynthetics that occurred in the 2000 Chi-chi Earthquake prompted the need to verify the seismic behavior and stability of such reinforced earth walls. In this study, a series of shaking table tests was carried out using a 1/33 scale model of a reinforced earth wall to investigate its seismic behavior and stability. Results indicated that no significant deformation of the reinforced earth wall occurred until the shaking acceleration reached a certain level, and after that level was exceeded the top of the wall gradually shifted forward. The length of reinforcements was crucial to the seismic stability of the reinforced earth wall, while the vertical interval between reinforcements was found less significant than the length. With regard to the shaking direction, shaking in the vertical direction caused very little deformation in the reinforced earth wall. Maximum shaking acceleration and the number of waves around the maximum shaking acceleration were important factors affecting deformation behavior.