Based on plane wave expansion method, the influence of factors such as lattice structure, dielectric constant ratio and filling ratio on three-dimensional photonic crystals with fcc, diamond and woodpile structures is studied. Of these structures, the fcc structure, owing to its high symmetry, is only fit for close-packed lattice prepared by inverted-opal method. The diamond structure easily generates good complete band gaps with high band gap ratio, and also the complete forbidden band that is needed can be obtained by adjusting some parameters in the experiment. The woodpile structure can produce big band gaps in a wider parameter range than the other two structures, which offers convenience for preparing three-dimensional photonic crystals in the laboratory. For all three kinds of three-dimensional photonic crystal structures, their band gap width and band gap ratio can be improved with the increase of dielectric constant ratio. In this paper, some interesting phenomena not noticed in the former papers are also presented.