In this paper, the internal thermal field and heat flow vector distributions of high power vertical-cavity surface-emitting semiconductor lasers (VCSELs), which is based on AlN film and SiO2 film passivation layers, were analyzed using ANSYS finite-element software. The simulation results proved that the AlN film passivation layer has better features than the SiO2 film passivation layers, and can make the device work in a more stable status, which also improves the device characteristics. Through the simulation, it was found that the Rthjc of VCSEL in AlN film was 3.12 K/W and the Rthjc of VCSEL in SiO2 film was 4.77 K/W. Comparison with the experimental values that the AlN film of 3.59 K/W and the SiO2 film of 4.82 K/W shows that simulation results are in good agreement with the experimental results. The proposed research works prove that the AlN film passivation layer has better thermal features than SiO2 film passivation layer.