To promote the coding capacity of quantum light sources in quantum information processing is an urgent problem to be solved in the development of quantum technology. As a unique degree of freedom for photons, the spatial pattern distribution of orbital angular momentum will form an infinite-dimensional orthogonal solution in Hilbert space. Therefore, encoding with the orbital angular momentum of photons can greatly increase the capacity of informationprocessing and is an important resource for high dimensional quantum information processing. A quantum light source with a two-level system can be equivalent to a point light source, and modulating the quantum light source to generate orbital angular momentum at the micro-nano scale is one of the effective ways to expand the coding dimension of on-chip integrated quantum light source. This article mainly discusses the properties of the superposition state of orbital angular momentum generated by point light source in micro-ring resonator. Firstly, the modulation mechanism on the orbital angular momentum generated by the point light source in the microring resonator with angular gratings is introduced. Then, the influence of the cavity quantum electrodynamics effect of the microring resonator on the radiation rate and collection efficiency of the point light source emitter is investigated, and thesingle photon purity is also discussed. Finally, the electric field distribution, phase distribution and vector polarization characteristics of the superposition state of orbital angular momentum produced by the point light source are investigated. Not only the effect of the point light source at different positions in the microring cavity on the cavity mode and the properties of orbital angular momentum, but also the mode purity of the single-photon orbital angular momentum states is analyzed in detail.This research provides an effective method for the development of integrated optical quantum devices carrying orbital angular momentum, which will promote the further understanding of the mechanism and properties of the orbital angular momentum generatedat the micro-nano scale.