The angular emission spectra of the distributed feedback (DFB) cavity are investigated theoretically and experimentally. An angular emission model of the relationship between the DFB cavity and its angular emission spectra is proposed. In the model, the DFB cavity can be decomposed into two parts: a grating and an active waveguide layer. So, the angular emission spectra of the DFB cavity are mainly determined by the period of the grating, the thickness of the waveguide and the material absorption during the feedback process. The theoretical model agrees well with the experimental results. It provides a convenient estimate for designing more efficient DFB polymer lasers and highly directional emission devices.