As a kind of newly developed technology, IR polarization works well in enhancing the contrast between objects and background, and discriminating camouflaged objects． An IR polarization imaging system is set up, several kinds of sample plates are made, and experiments at different observing angles are carried out． The effects of roughness, target materials and observing angle on IR polarization characteristics are studied． Experiments results show that the polarization characteristic is more obvious for smooth targets． Targets of different materials differ in polarization characteristics． As the observing angle increases, the rate of polarization increases too． Roughness, observing angles and target material are important factors that affect the results of polarimetric characteristics． Research on influencing factors of targets polarization characteristics has an important guiding effect on the use of polarization detecting．