A novel supercell lattice method (SLM), induced from both the plane wave expansion method (PWM) and the semi vector method, is presented to analyze the photonic crystal fibers (PCF). The electric field is still expanded with the Hermite-Gaussian function, the dielectric constant of the PCF missing the center air hole can be considered as the sum of two perfect PCFs, which have different dielectric constant and different structure parameters (the hole pitch, the hole diameter). The periodical dielectric structures of the two perfect PCFs are expanded in cosine function with different periods. From the wave equation and the properties of Hermite-Gaussian function, the propagation characteristics of the PCF, such as the mode field distribution, birefringence, the dispersion property, can be obtained. The accuracy of the SLM can be scaled by the birefringence because the ideal triangular lattice PCF has no birefringence based on the group theory.