In this dissertation, the internal field of a laboratory of desert environment simulation was studied and analyzed. According to the sizes of the axial-fans and the laboratory, the numerical models of the fans and the laboratory were built with CAD and GAMBIT. The numerical simulation was carried out with commercial CFD software-Fluent and the k-ε model was established to research this project. The variation effect of the height of the solar simulator and the opening with exhaust hood on the flow field was also investigated. And the demand of different velocity outlet conditions could be met by changing fan rotational speed. From the results of the simulation and the experiment, it is shown that the method of numerical simulation coupling fan and laboratory model was feasible to the simulation of the laboratory.