Herein, a double-periodic photonic crystal structure array is designed by double-cone interferometry using 3+3 beams, and nano-focusing effect is studied as well. The small period of photonic crystal lattice and large period of photonic array can be changed by adjusting the incremental angle between inner and outer cones. The structure and shape of gradient photonic crystal lattice can be changed by adjusting the intensity and polarization direction of the beam. Fourier transform method is used to study the nano-focusing effect of the designed photonic crystal structure. The structure is very important for improving the extraction efficiency, optical display, optical coupling, and optical integration of light emitting diodes.