In this paper, a method for optimizing the performance of photonic crystal fiber (PCF)polarization filter based on the surface plasmon resonance (SPR) effect was proposed. The method was realized by using the asymmetry of the metal filler and the refractive index environment around the core. The study shows that the effective refractive index of the surrounding materials could be effectively controlled by the special design features of the core and metal filler of the photonic crystal fiber to realize the birefringence effect of the metal plasma mode and the birefringence of the core mode of the fiber. Therefore, when the core mode and metal surface plasmon mode satisfy the phase matching conditions, the polarization filtering effect could be achieved, and a good extinction ratio could be obtained without complex structure design of the photonic crystal fiber, which reduced the difficulty of device preparation and solved the problem that the designed fiber structure could not realize the actual preparation.