The invention relates to a thermal design method used for radar incubator TEC (Thermo Electric Cooler) model selection. The method comprises the following steps that: through theoretical calculation,finishing the model selection of a TEC, a fan and a radiator in a radar incubator; establishing the three-dimensional model of the radiator incubator; establishing a three-dimensional gridding calculation domain; carrying out simulation calculation on the radar incubator to obtain an initial simulation result; and establishing the contour line cloud atlas of temperature distribution and the flow path line of fluid, and improving the internal structure and layout of the radar incubator which does not conform to job requirements. By use of the method, a research and development period can be shortened, and economic benefits are improved. In a practical use process, the radar incubator obtained through the method of the invention has a good heat dissipation effect, and meanwhile, the radar incubator has the advantages of compact structure, miniaturization and good waterproof sealing and electromagnetic shielding effects.