A novel simple structure of photonic crystal fiber is optimized based on silica as the backing material, which has a cladding of hexagonal symmetric array uniform circle air hole and a larger the area of fiber core by missing central air column and reducing six air holes around the central core. Based on finite difference time domain method with the boundary conditions of anisotropic perfectly matched layers, its dispersion, nonlinear, confinement loss and fundamental mode field is numerically investigated. Numerical results indicate that the proposed fiber shows ultra-low loss, low non-linear and flattened dispersion performance. Its confinement loss is less than 10－7 dB·km－1 over communication band, which is 2.93×10－8 dB·km－1 and 7.33×10－10 dB·km－1 at wavelength of 1.55 μm and 1.31 μm, respectively. Furthermore, it appears double zero dispersion point and a certain ultra-flatten dispersion in the longer wavelength range, which flattened dispersion is 0±1.7 ps·km－1·nm－1 over 1.05~1.65 μm. Another, its non-linear coefficient is only 4.88 km－1W－1 at wavelength of 1.55 μm. It is obviously to obtained admirable application in the field of long distance high speed optical communication system due to its ultra-low loss low non-linear and flatten dispersion capability.