An ultra-short polarization beam splitter (PBS) based on a dual-core photonic crystal fiber (PCF) with the surface plasmon resonance effect is proposed. The finite-element method is used to investigate the coupling characteristics between the core mode and surface plasmon polariton mode. The influences of the PCF structure parameters on the coupling length and coupling length ratio are also investigated. The normalized output powers of the x-polarization and y-polarization are calculated, and the optimized PBS achieves an ultra-short length of 62.5 μm. The splitting bandwidth of 110 nm (1.51 to 1.61 μm) is achieved when the extinction ratio (ER) is less than −20 dB. The minimum ER reaches −71 dB at the wavelength of 1.55 μm. The proposed PBS has an important application in high-speed optical communication systems.