To realize the quantitative measurement of space target infrared radiation, infrared radiation measurement system must be calibrated in advance. Based on the deficiencies of conventional calibration method for large aperture infrared radiation measurement system, through analysis of calibration and measurement working principle of space object infrared radiation measurement system, a new calibration method was proposed which combined inner blackbody calibration and astronomical star calibration. Respond relation between matching mirror and detector was deduced when using inner blackbody as standard radiation source. Besides, calibration relation between infrared star radiation and transmittance of large-aperture primary mirror system was also deduced when using infrared star as standard radiation source. Then response relation of infrared measurement system was also advanced. The experiments show that the curve slope accuracy of new method is within 4% compared with traditional full-aperture blackbody calibration method. This new method reduces manufacture difficulty of calibration system, has advantages of easy operation, high efficiency of calibration etc.