For the thermal blooming of the beam path indoor, solving the coupling equations of optical field and Fluent field completely is a meaningful and important subject. By means of segregated solving the coupling equations, a model for simulating the coupling equations is described based on the software of the Fluent. The procedure is compiled by the user defined equations, the parameters of the fluid are inputted and the distribution of the beam intensity is calculated. The absorbed laser energy is added to the energy equation of the fluency as the energy source. The fluency equations are solved by virtue of the Fluent software. As the straight tube with the round section, the results obtained by the theoretical methods are consistent with the outcomes achieved by the established model.