A novel polarization channel drop filter (PCDF) based on two-dimensional (2D) photonic crystals (PCs) is presented. It consists of two line defect waveguides and two point defect micro-cavities. In the line-defect waveguides, the transverse-electric (TE) and transverse-magnetic (TM) polarization lights are guided using photonic band-gap and total internal reflection effect, respectively. The light at the resonant frequency for TE polarization can be transferred from one waveguide to the other using the proposed system. Compared with the existing four-port PCDF based on PCs, the three-port structure can realize a multi-channel wavelength system of PCDF more easily and can be an essential device in future polarization wavelength division multiplexing (PWDM) systems.