Abstract: In this work, I propose a scheme about a single graphene nanoribbon (GNR) emitter in a microcavity, and focus on a fully-quantum-mechanical treatment model with the excitonic interaction included to investigate the photon properties and lasing action. When the single armchair-edged GNRs (AGNRs) microcavity system is pumped, the exciton-photon coupling provides more photons and enhances the photon emission process, making it essentially a lasing object. The theoretical results demonstrated that single AGNR in a semiconductor microcavity system maybe serve as a nanolaser with ultralow lasing threshold.