In this paper a new type of reinforced concrete four-way rib hollow slab was proposed by the authors first. Further in order to research on the mechanical properties of the new floor slab the other two common slabs were compared with the new one, that was two-way rib hollow slab and solid slab. The rational finite element (FE) models of the three kinds of slabs supported by four corner columns were built up respectively by ANSYS. The deflection and stress of the three kinds of slabs under three load cases were calculated separately, on the basis of which thorough comparisons and analysis were carried out. The study results showed that the new reinforced concrete four-way rib hollow floor slab has superior mechanical properties.