The invention discloses a photonic crystal waveguide diagonal mode interference FANO resonant structure. The structure comprises a two-dimensional photonic crystal linetype waveguide formed through distribution of a plurality of dielectric cylinders with the refractive index, the two-dimensional photonic crystal linetype waveguide comprises two waveguide ports and one point defect resonant cavity,wherein the two waveguide ports are arranged on the two sides of the point defect resonant cavity, the point defect resonant cavity comprises four dielectric cylinders and one point defect dielectriccylinder with one cross section being square or similar to square, two dielectric cylinders are symmetrically arranged on the two sides of the point defect dielectric cylinder respectively, and the centers of the four dielectric cylinders and the point defect dielectric cylinder are distributed and arranged at equal intervals. The structure provided by the invention is compact, bright mode and dark mode of Fano resonance can be conveniently controlled, and Fano resonance is easy to achieve integration with other photonic crystal parts.