A photonic crystal fiber was analyzed which produces birefringence by changing the refractive index of the cladding radial holes and the influence of geometric symmetry on the birefringence feature of this fiber was compared. The finite element method was used in the data analysis of features such as the electric-field distribution, normalized birefringence and polarization of the fundamental mode of the fiber. The results implied that the birefringence feature of the photonic crystal fiber can be controlled by adjusting the medium refractive index of cladding radial holes, diameter of an air hole and space size between the cladding air holes. If the fiber’s geometric structure and refractive index of the radial holes are changed at the same time, the birefringence effect will increase with a result of a higher order of magnitude than ordinary polarization-maintaining fiber. This result provides theoretical basis for design and manufacturing of the photonic crystal fiber.