A new structure of two-dimensional square lattice photonic crystal waveguide beaming of light emitting with filtering function is proposed in this paper. The output port of the structure is a stepped horn shape, which enhances the beaming of light emitting through the interference between the radiation wave and the surface wave generated by the horn surface, thereby greatly improving the effective propagation distance. The structure is analyzed using the finite-difference time-domain method, and by introducing two coupled filters at the front end of the horn, selective filtering of incident light waves at specific wavelengths can be achieved. The results showed that when the wavelengths were 1.505 μm and 1.516 μm, the incident light waves were selectively filtered, with the filtering efficiencies reaching 99.64% and 99.02%, respectively. Meanwhile, due to the use of the stepped horn structure, the beaming of the emitted light waves in other bands (wavelengths ranging from 1.460μm~1.480μm and 1.540μm~1.560μm) is greatly enhanced, and the effective transmission distance is greatly increased.