This paper presents some methods to simulate the structure of tall building with hollow flat slabs using structural analysis software Etabs. These methods then are applied to investigate the effects of hollow slab modeling on the dynamic behavior of the tall buildings. A couple of tall structure systems of the real buildings with porous hollow core floors of 20 and 40 storeys, which are in the current common height range of tall buildings in Vietnam, are used for analysis. The dynamic responses of these structural systems including the period of natural vibration, inter-storey drift, and absolute horizontal displacement at story levels of the structures are considered. The analysis results may provide the database for structural engineers to choose the appropriate method when analyzing tall structures with hollow floors as well as to understand the dynamic behavior of tall structures with respect to simulation methods.