We report a new method for second harmonic generation (SHG) by using centro-symmetric dielectric, of which 'chi'(2) is zero, rather than common nonlinear material. By designing the unique structure of centro-symmetric dielectric, which consists of two photonic crystals and several air waveguides, the efficient second-harmonic (SH) has obtained for the sharp enhancement of the electric quadrupole polarization. Based on finite difference time domain (FDTD) algorithm, the electromagnetic field distribution in the structure and the intensity of SH along the waveguide are analyzed. When the beam intensity of the pumping wave is 1.3 MW/mm2, the conversion efficiency of power is 0.307% for a photonic crystal waveguide with a length of 40 'mu'm.