The invention discloses a photonic crystal multimode optical fiber with completely-separated intrinsic modes. The photonic crystal multimode optical fiber comprises a birefringent fiber core which isasymmetrical in horizontal and vertical directions, an inner cladding layer formed by arranging circular air holes in a hexagonal array and an outer cladding layer formed by pure silicon dioxide. Theoptical fiber supports more than 10 intrinsic modes, and the effective refractive index difference between any two adjacent modes is greater than 1x10<-4> and even greater than 1x10<-3>, that is, allmodes are completely separated, thereby realizing the multichannel intrinsic-mode multiplexing communication of the optical fiber. According to the invention, the mode division multiplexing transmission is directly carried out on the basis of an optical fiber intrinsic mode, the supported intrinsic modes are completely separated and simplified, and the intrinsic mode stable transmission of the multichannel optical fiber can be realized without MIMO-DSP technology. The photonic crystal multi-mode optical fiber provided by the invention is completely composed of a pure silicon dioxide matrix andan air hole lattice, is based on the existing photonic crystal optical fiber manufacturing process, and is convenient for implementing the actual drawing.