In order to evaluate the importance of the radiation influence between buildings and provide theoretical support for the infrared multispectral simulation method and ATR algorithm research, some research in waveband 3-5 μm and 8-12 μm was done and a radiation influence calculation model between buildings was built in this paper. When the direct solar radiation existed, it was not necessary to consider the radiation influence between buildings in 3-5 μm, because the influence was tiny enough to be ignored, while it should not be ignored in 8-12 μm because of the apparent influence. A virtual scene with two cooling towers was build and the radiation in 8 μm, 9 μm, 10 μm, 11 μm and 12 μm were selected to calculate the radiation influence between the cooling towers. According to the result, the radiation influence in 8 μm, 9 μm and 10 μm is greater than 10%, while that in 11 μm and 12 μm was smaller. The scene simulation for the radiation influence between the cooling towers is done, which shows the radiation influence at different wavelength with the changes of radiation distance.