[en] A kind of novel photonic crystal fiber grating based on structural change was studied, the effective refractive index induced by structural change was computed using Multipole Method, the relationship between the effective refractive index and the shrinkage of air-holes was got. Moreover, the fabrication principle was proved in the mathematics way. A model of photonic crystal fiber grating based on structural change was built, the transmission characteristics were analysed with Coupled Mode Theory. The emphasis of this study was the impacts of the rings of air-holes in the cladding, the rings of air-holes shrinkage and the degree of air-holes shrinkage on the transmission characteristics. The research results indicate that the periodic air-holes shrinkage can form grating, not only the degree of air-holes shrinkage, but also the shrinkage envelope has important effect on the magnitude and the distribution of the effective refractive index; the resonance wavelength, the resonance bandwidth and the intensity have relations to the rings of air-holes in the cladding, the rings of air-holes shrinkage, and the degree of air-holes shrinkage.