In this Letter, a new type of single-mode slotted laser used for an on-chip light source in photonic integrated circuits is proposed. An inclined light beam with a low vertical divergence angle can be directly coupled into the surface grating of the silicon to form an integrated light source. Experimentally, a III-V laser with a 54.6° inclined angle and a vertical divergence angle of 1.7° is achieved by introducing a kind of specially distributed microstructure. The side mode suppression ratio is better than 45 dB, and the continuous wave output power reaches 6.5 mW at room temperature. We report the inclined emitting microstructured single-mode laser with a low divergence angle for the first time, to the best of our knowledge.