In order to obtain photonic crystal fiber with high birefringence and flattened dispersion, we propose a new photonic crystal fiber structure with an elliptical air hole as the core surrounded by square air holes. In this paper, the effects of different fiber core ellipticity and different filled material on birefringence, dispersion and nonlinearity of photonic crystal fiber are discussed. The results show that at the wavelength of 1.55 μm, when the core ellipticity of the filled material is the same, the maximum birefringence value is 0.37 and the maximum value of nonlinear system is 277.76 W^-1×km^-1. When the fiber is filled with different materials, the maximum birefringence value is 0.34 and maximum nonlinear value is 307 W^-1×km^-1. In addition, in the wavelength range of 1.26 μm～1.8 μm, the nearly zerodispersion flattened characteristics are achieved. The range of variations is no more than ±12.5 ps/(nm×km), and the bandwidth is 0.6 μm.