Abstract: Infrared extra-large radiation area blackbody was used to simulate certain infrared characteristic target, widely used in different infrared detection, controlling and guiding equipment's field test. With the aperture of the IR imager used in space becoming larger, the area of the area blackbody was also becoming larger. Extra-large radiation area blackbody must be calibrated in vacuum cryogenic environment, for its performances satisfy the need of test. But there is still no measurement standard at home, it can not guarantee the accuracy and reliability of test results. A calibration device for infrared extra-large radiation area blackbody was presented in this paper, the calibration for emissivity, radiation temperature, uniformity of temperature field and stability of radiation temperature was realized, and good results were achieved. The calibration of infrared extra-large radiation area blackbody in vacuum cryogenic environment was realized by this device.