The spectral response measurement of space infrared camera with large aperture was introduced. The measure system had been developed, which included visible and infrared light source, monochromator, standard detectors, data acquisition system, parallel light tube, vacuum tank, turntable and the test camera. The bands of test camera were concentrated in water vapor, CO₂ absorption bands. In order to eliminate the impact of atmospheric absorption bands, parallel light tubes, test camera, turntable should be placed under vacuum condition, and the monochromator should be purged with nitrogen. The results show that, after purged with nitrogen, the spectrum precision is greatly improved and the spectrum at atmospheric absorption bands can be accurately measured.