A photonic crystal fiber (PCF) structure with low loss, broadband near-zero dispersion and high nonlinearity is proposed. The diameter of the air hole in the cladding increases gradually from the core to the cladding. The dispersion, loss and nonlinear characteristics of the PCF are analyzed by the multipole method through changing the air hole spacing, diameter and the number of air hole layers. Finally, the variation law of each characteristic is obtained and the optimal structure parameters of PCF are designed. The results show that the fiber has three zero dispersion points, the dispersion and dispersion slope is less than 0.27 ps·nm^-1·km^-1 and 0.008 ps·km^-1·nm^-2 respectively between 1.25 μm and 1.55 μm, and the loss is 0.021 dB/km at 1.55 μm. The nonlinear coefficients are 78.6 W^-1·km^-1, 60.4 W^-1·km^-1, and 38.2 W^-1·km^-1 at the femtosecond laser pumping wavelength 0.8 μm, 1.06 μm and 1.55 μm respectively.