The photonic; crystal of layer-by-layer ( LBL) structure is discussed in this paper. The structure of LBL photonic crystal is body-centered tetragonal (b.e.t) rather than face-centered tetragonal (f.c.t). For the LBL photonic crystal of f. e . e or b. e. e lattice, to obtain the full information on its Brillouin zone, the calculation of three restricted volumes is needed and our calculation result agrees well with the experiment. The allotments of optical fields of eigemnodes in a dielectric material are also calculated. In the dielectric material, for the eigenmode at the bottom of the forbidden gap, electric field takes a larger fraction of the whole energy than magnetic field, while for the eigenmode at the top of the forbidden gap, the allotment of energy is just the other way round. The photonic; crystal of layer-by-layer (LBL) structure is discussed in this paper. The structure of LBL photonic crystal is body-centered tetragonal (bet) rather than face-centered tetragonal (fct). For the LBL photonic crystal of f. e. e or e e lattice, to obtain the full information on its Brillouin zone, the calculation of three restricted volumes is needed and our calculation result agrees well with the experiment. The allotments of optical fields of eigemnodes in a dielectric material are In the dielectric material, for the eigenmode at the bottom of the forbidden gap, the electric field takes a larger fraction of the whole energy than the magnetic field, while for the eigenmode at the top of the forbidden gap, the allotment of energy is just the other way round.