Aiming at the requirements of high nonlinearity with low confinement loss of photonic crystal fiber (PCF), we design an octagonal circular-air-holes structure of PCF. Based on full vector finite element method with the boundary condition of perfectly matched layers, its effective index, nonlinear coefficient and confinement loss are numerically investigated. The numerical results indicate that the proposed fiber shows higher nonlinearity, lower confinement loss and stronger confinement ability of mode-field profile. A better result can be gotten when adjusting the parameters of PCF with d1=0.77 μm, d2=0.86 μm. The high nonlinear coefficient of 37.6 km-1·W-1 and low confinement loss of 0.7×10-17 dB/km are found at 1.55 μm wavelength.