A novel and general model for light propagation in photonic crystal fibers (PCF) is proposed. A new method for constructing supercell lattice is proposed, the transverse index profile of PCF is represented with overlapping of two periodic structures and the modal field is decomposed by using Hermite-Gaussian functions. The propagation constant and the mode field distribution of the PCF can be calculated by recasting the Maxwell equations into matrix eigenvalue system. The transmission properties of PCF including modal field distributions, dispersion properties, polarization properties and effective area are analyzed. As a general method, it is an accurate and efficient model for square, honeycomb lattice and elliptical-hole PCF.