Based on the principle analysis of thermal IR image reconstruction, thermal image negative of corresponding transmission was made according to gray distribution characters of the required reproduction thermal image，and a new method to generate thermal IR image by coating different transmission films is put forward, for investigating the effect of the description accuracy of the object and background thermal radiation characteristics on the target acquisition, recognition and tracking by IR target seeker. It is verified that this method could reproduce the properties and details of both targets and backgrounds by the thermal IR reproduction experiment and the algorithm of image correlation coefficient. The new method can not only be used in testing and assessing the properties of thermal IR target seekers and highprecision guided weapons, but also can be taken as a new camouflage technique for military targets.