A theoretical study on 13μm GaAs-based quantum dot vertical-cavity surface- emitting lasers (VCSELs) was made. Investigation of the influence of VCSELs on t he optical confinement factors and the optical loss and the calculation of the m aterial gain of the assembled InGaAs/GaAs quantum dots. Analysis of the threshol d characteristic was made and the multi-wavelength cavity and multilayer quantum_dot stack structure is found to be more suitable for quantum dot VCSELs.