Tall buildings structure has been a considerable increase in both residential and commercial as well as modern Trend structures. There are two systems comprise the most attractive and commonly used now a days are flat slab and shear wall system. Flat slab is most widely used system in reinforced concrete construction in offices, industrial buildings etc. It supports floor slab without beams. When it comes to seismic performance or lateral force flat slab tall buildings without shear wall is relatively less when compared to with shearwall.in this study I have done two models of flats slab tall buildings one with shear wall and another one without shear wall by using ETABS software. The comparison of analysis results will take place in order to see how both a buildings are performing under lateral and seismic loads and finding a seismic parameters like time period, base shear, lateral displacement, and storey displacement are checked out.