Electrically controlled two-dimensional-triangular lattice polymer dis persed liquid crystal (PDLC) photonic crystals are fabricated and studied in this paper.In order to im prove the existing fabrication method and electrical controlled characteristics of PDLC photonic crystals,the phase se paration between polymer and liquid crystal is induced by the 532nm laser beam interfere nce pattern.The twice holographic exposures with different time are utilized in this paper,wh ich means that after the first exposure,the sample is rotated about 60° along the central normal line of the sample base plate,and then is exposed again.The experimental results demonstrate that the time of twice expo sures has great influence on the phase separation between polymer and liquid crystal.In addition,the two dimens ional photonic crystal,which is fabricated with the optimized condition,shows regular triangular lattice periodi c ity distribution with a polarizing microscope.The diffraction patte rns of the PDLC photonic crystals with different lattice constants are detected by the 633nm He-Ne laser,when the pho tonic crystals are not under external electric field.The electro-optical charac teristics of the first-order diffraction show that the diffraction efficiency of PDLC photonic crystal can be e ffectively adjusted through external electric field.