The interaction of the cavity electromagnetic field with the two-level emitter is described by cavity quantum electrodynamics (CQED). A pulsed micro-laser is an array of semiconductor quantum dots (QDs) embedded in an optical micro-cavity. This is one of the basic tools of quantum information technology. In this study, the energy eigenvalues variations and the quantum efficiency of a micro-laser system includes a QD with a decay rate of 0.8μeV embedded in the different micro-cavities, were investigated. The results show that with the increasing coherent interaction rate of micro-laser system, the energy eigenvalues variations of this optical system also increase. The quantum efficiency for this nano-optical system was studied. The results show the smaller micro-cavity decay rate, the higher quantum efficiency at smaller coherent interaction rate. Then, the optimal value of the micro-cavity decay rate was obtained in order to achieve the maximum quantum efficiency. The calculation results showed that the highest quantum efficiency occurs for optical parameters γa=0.8μeV, g=95μeV, γc=177.7μeV, and ηmax=0.991.