Abstract: Vacuum blackbody radiation sources are crucial instruments for the radiometric calibration of infrared remote sensing payloads in ground laboratories. To meet the trend of infrared remote sensing payloads towards larger apertures, wider temperature ranges, and higher quantification, a vacuum blackbody radiation source with a 300 mm aperture, a temperature range of 160–380 K, and an emissivity of 0.9975 was developed. This paper introduces the working principle and structural design of the large aperture and wide temperature range vacuum blackbody radiation source. It includes the calculation of emissivity and thermal simulation of the blackbody. The uniformity and stability of the bottom temperature of the blackbody within the 160–380 K range under vacuum low-temperature conditions were tested. The results show that the bottom temperature uniformity is better than 0.120 K and the temperature control stability is better than 0.031 K/30 min. The blackbody cavity emissivity was measured using a method based on controlling environmental radiation, and the spectral radiance temperature was measured using a vacuum low-background infrared radiance temperature standard device. The combined standard uncertainties of the radiance temperature at 10 μm were 0.044 K@160 K, 0.099 K@280 K, 0.095 K@380 K, 0.122 K@380 K. The developed vacuum blackbody radiation source with a large aperture and wide temperature range can meet the radiometric calibration requirements of infrared remote sensing payloads in ground laboratories, supporting the enhancement of China's quantitative level of infrared remote sensing.