Emissivity is an important thermophysical properties parameter of representing objects surface radiation characteristics,which is related to various factors,such as temperature,measurement wavelength,surface oxidization and surface roughness.The research on its change characteristics is of great significance for infrared measurement.In this paper,under the atmospheric conditions,with the temperature of 800 K to 1160 K,measurement wavelength of 1.5 μm and bandwidth 20 nm,the effect of oxidation characteristics on spectral emissivity of steel SPHC samples was studied.In the experiment,every 40 K is used as a temperature measurement point.When the sample reaches measurement temperature,it will be heated for over 3 h,and the spectral emissivity is recorded once for every 5 min.The experiment results how that:①under a relatively low temperature of 800 K and 840 K,Fe and O2 produce Fe2O3.At this temperature,the increase of oxidation film mainly comes from this reaction;②under the temperature of a bit lower than 960 K,Fe2O3 and Fe produce FeO,this process goes slowly,and it takes longer time for the sample surface spectral emissivity to be stable;③at the temperature of higher than 1120 K,the spectral emissivity basically remains unchanged,the oxidation film of FeO on the sample surface generates quickly.On the other hand,in the same heating time,by means of fitting,by analyzing the influence of temperature on spectral emissivity,we come to the conclusion that the relationship model between temperature and emissivity in different heating time is the same as the real model description.In the end,in the real application,when the temperature of steel is measured,the influence of surface oxidization on spectral emissivity must be taken fully consideration.