For small objects in deep space exploration, the radiation temperature is about 100 K to 420 K. According to Wien's displacement law, deep space exploration targets cover the ultra-wide spectral range of 5 μm to 50 μm, and high-precision on-board calibration is the key to the accurate detection of deep space exploration loads. Therefore, it is necessary to develop an on-board calibration source with high emissivity and high temperature stability of ultra-wide spectrum. Aiming at the technical problems of detecting ultra-wide spectrum, high reflectivity and high temperature stability of radiometric calibration blackbody source on ultra-wide spectrum stars in deep space, this paper carries out in-depth research and experimental verification from several aspects such as simulation, key component design and sample detection methods, so as to ensure the engineering realization and application of high-index precision radiometric calibration blackbody source on stars. COMSOL Multiphysics software simulation based on finite element method, microstructure design of blackbody source, emittance detection method of blackbody source and radiation calibration test in laboratory were studied.Firstly, starting from the parameter optimization design of the blackbody surface microstructure, the means of improving the emissivity is transformed from qualitative research to quantitative calculation. The optimal design parameters for wide-spectrum emissivity design are obtained by optimizing the microstructure of the radiating surface of the on-board calibration blackbody source, and then carbon-based ultra-black coating material is selected to further improve the spectral emissivity of the blackbody source. The microstructure optimization junction and the superblack coating of the blackbody source on the star are optimized to increase the emissivity of the blackbody source on the star from 5 μm to 50 μm in the spectral range to 0.986, in which the ultra-wide spectrum is realized. Depending on the superblack coating, each material has different intrinsic radiation ability in different bands, and the coating is a composite porous structure, which makes it have high emission ability in a wide band. Secondly, by careful selection of blackbody source temperature controller and optimal design of temperature control system, the temperature measurement accuracy and stability of on-board calibration source are improved. The MF61 series film NTC thermistor is embedded on the blackbody surface to monitor the temperature of the blackbody surface in real time. The Thermoelectric Cooler (TEC) is a heating and cooling device that has been developed utilizing the Seebeck effect; The high-precision temperature measuring device is capable of accurately and effectively measuring the real-time surface temperature of a blackbody. It utilizes the high-precision voltage reference REF6225 and precision metal resistance current limiting to provide constant current output for NTC as a constant current source, while employing the precision digital-to-analog conversion chip ADS124S08 and four-wire resistance temperature detector for temperature measurement. Using Ohm's law, the voltage value is converted and fed back to the high precision temperature measurement circuit. The temperature measuring circuit sends control instructions to TEC drive current through comparison and analysis with the actual required temperature. The power management chip TPS63020 is used as controller, which can pull and inject current to drive TEC, and then heats up or cool down TEC to control the blackbody surface temperature. The temperature stability of the on-board calibration blackbody source reaches 0.16 K. Finally, the design and process reliability of the blackbody source are tested by comprehensive parameter measurement and evaluation. The design results are verified by measuring the emissivity of the blackbody source and the temperature stability of the blackbody source in the vacuum environment. The test results show that the spectral range of ultra-wide spectral calibration blackbody source for deep space detection is 5 μm to 50 μm, the normal average emissivity is 0.986, and the temperature stability reaches 0.16 K. The blackbody source will greatly improve the spectral range of high-emissivity radiometric calibration sources, and provide basic support for on-orbit high-precision radiometric calibration of deep space exploration loads.