The effect of intensity threshold on the filling ratio was analyzed by calculating the intensity spatial distribution. The photonic band gap properties of two-dimensional triangular lattice fabricated by holographic lithography are investigated numerically. The influences of intensity threshold and dielectric contrast, on photonic gap are comprehensively studied by plane wave expansion method. Calculations of band structure as a function of the intensity threshold show that the PBG of positive structure opens for TM and TE polarization separate, and the negative structure has the complete PBG. The complete PBG does not increase monotonically with dielectric contrast ratio, but has a peak value instead by studying the relation between the complete PBG and the dielectric contrast ratio. The optimal dielectric contrast is 22 when intensity threshold is 0.2.