Abstract: The temperature and area of blackbody were researched for simulating the real target in the experiments of infrared countermeasure. First of all, the two principles that should be observed were proposed to effectively simulate infrared radiation characteristic of real object: equality of irradiance and solid angle. The formula which calculates the temperature of blackbody was secondly deduced based on the infrared theories. At last, Jian-7 plane was taken as real target; its infrared radiation characteristic was computed in the different viewing angle, the influence of atmospheric transmittance and path radiation luminance were also taken into account. The temperature and area of blackbody were studied in different viewing angle and distance of the seeker and target. The results show that the variable trend of blackbody's temperature agrees with that of target's radiation luminance and the variable trend of blackbody's area agrees with that of target's projected area under the two principles. The research fruit can provide theoretical basis and data reference for carrying out the countermeasure experiment of infrared guided weapon.