A method for designing two-dimensional photonic crystal polarization splitters is put forward. Optimal structure of a two-dimensional photonic crystal with a t riangular lattice of Ge rectanglular rods in BaF2 is presented. It is shown ho w a maximum photonic band-gap for TE mode is obtained by choosing the proper wid th of the rectangular rods. The two-dimensional bandgap for TE mode of this design is 0.083(2πc/a, here a is the period of grating). The polarization frequency band corresponds to a wavelength band ranging from 172 to 24μm, with the theoretical relative bandwidth being 33.1%. The fabrication of such a pho tonic crystal polarization splitter is an easy process based on coating films on the grating and is suitable for industrial making.