The influence of temperature variation on the imaging effectiveness of a lens is called thermal dispersion. To make a lens have stable imaging quality in a certain temperature range, usually some compensation measures for athermalization should be taken. Normalized coefficients are the important parts of an athermal mathematical model. The concepts of normalized coefficients and their application in athermal technologies are discussed. The development ideas and trends of athermal technologies for infrared optical systems are presented on the basis of the related papers published in China.