In this paper, the correlation model for atmospheric parameters and transmittance is established. First transmit transmittance models for each variable such as temperature, humidity, visibility, rainfall and beam wavelength, altitude, and zenith angle. These models then are cascaded. We deduce the atmospheric transmittance profile of light waves in the 0.3 um-15 um band. Moreover, atmospheric transmittances under different atmospheric environments are analyzed, and the window transformation trend of the transmittance is described. It is important for the calculation of the channel attenuation of the atmospheric optical communication system.