Abstarct: Mechanically Stabilized Earth Walls (MSE WALLS), are a typical of retaining structure constructed within soil using reinforcing elements such as bands, mextal networks, and polymeric materials. The ability to withstand differential settlements, no need to rigid support, high ductility, the possibility of building with a height of over 25m, lower cost, availability of materials and simplicity of construction are the benefit of these wall with respect to rigid & contilever walls which to their development. These walls are made of three elements of facing, reinforcement and backfill that are stabilized by interaction between facing and reinforcement elements with soil. Since seismic design of the walls by force methods such as pseudo- static or pseudo-dynamic methods is not able to calculate of their deformation, so in this study, they have been parametrically addressed variables like surface settlement of backfill, sideway displacement of facing, permanent dislocation of wall, and mobilized force in the bands via a performance baxsed new design approach through a Dynamic Analysis of Time History upon finite element method (FEM) by two software of Plaxis and Geostudio to improve seismic performance of the walls. Factors examined their impacts on wall performance in parametric studies were included; the length and stiffness of top reinforcement, lack of compaction of a soil laxyer next to facing, reinforcement length to wall height ratio, the distribution of reinforcements, use of segmental facing and type of earthquake. The results of the study are as follow; increasing the length of upper reinforcement, contrary to its stiffness, has a significant effect on decreasing dynamically settlement of backfill surface, facing lateral displacement and permanent displacement of wall. The lack of compaction of a soil laxyer adjacent to facing which is among errors during construction of the walls, increases permanent displacement dramatically which was up to 60% in the study; Amount of 0.7 for the ratio of reinforcement length to wall height, recommended by FHWA, due to the rate of settlement and lateral displacement obtained from the time history analysis, also suitable in seismic conditions. Reinforcement distribution with less vertical distance leads to reduced settlement of the backfill surface. For several earthquakes with similar maximum acceleration amplitude and duration, the greater the earthquake frequency rate change, the greater dynamically settlement of backfill surface and facing sideway displacement.