As the infrared polarization system is very sensitive to the observation factors like observing-angle,light waveband,light intensity,target material and the atmospheric transmittance,it is necessary to study on those factors to make sure the infrared-polarization system working in a good status.First,the polarization state of the target was described by Fresnel Reflection and Kerchief’s law;then,an experimental system for infrared-polarization imaging was set up with an infrared polariscope which was made of BaF2 (waveband 2~30 μm);third,several contradistinctive experiments had been done with different imaging factors such as different observing-angles,light waveband,light intensity and different target’s properties to analyze the results and get the conclusions.The experiments show the similar results compared to theoretical analysis and simulation:the contrast of the target and the background is enhanced in all those experiments;as the angle of incidence get close to the Brewster’s angle,the degree of polarization get bigger,but the Brewster’s angle may not be the best observing angle for infrared polarization imaging system,and this is an innovation of the research;stronger light intensity and the glazed surface of the target also make the degree of polarization bigger.The conclusions may be helpful to target-searching and polarization imaging.