A primary description is made of the process of establishing the FY2D OLR inverse model, and the model comparison is conducted between NOAA and FY2D. The earthatmosphere infrared radiation transfer equation is introduced. The radiances and OLR at the top of atmosphere for 3812 sounding profiles, the channel radiance for FY2D window channel 1, 2 and water vapor channel, and the narrowband radiative flux of three FY2D channels for 3812 soundings are calculated, and the limbdarken correction equations for the 3 channel radiances are established. The FY2D OLR inverse model is devised based on the narrowband flux and OLR scattering graphs for 3812 soundings. By comparing the NOAA17 AVHRR channel 5 OLR inverse model with the FY2D window channel 2 OLR inverse model, it is concluded that the two satellites OLR inverse models are nearly the same. An example of the FY2D OLR product and the product quality examination is also given.