We propose a Y-type polarization beam splitter based on internal polarization-selective defects within crystal waveguides in a two-dimensional square-lattice photonic crystal with solid rods. When the nonpolarized light launches from the input port, different polarizations will be separated and can only transmit through their own channel. It is demonstrated by finite element method that the proposed structure can achieve good performance for both the transverse electric and transverse magnetic polarizations in a wide range of wavelength, with the polarization extinction ratio more than 25 dB, the degree of polarization nearly 1, and the insert loss less than 0.5 dB, respectively.