Abstract: To better understand and suppress the ground recovery of the space radiation damage in spacecraft materials, S781 white paint samples were selected to be put under irradiation of 90 keV electrons in a simulated space environment. After that, the radiation-induced spectral reflectance change and the solar absorptance change were measured in the vacuum, then with air fed into the vacuum chamber, the samples were exposed to the air for several hours. The results show that the optical degradation of S781 white paints is mainly recovered in just several minutes under the air exposure. Furthermore, a liquid-nitrogen environment can conserve the electron irradiation damage and the optical degradation of the S781 white paints. The conservation mechanism of the liquid nitrogen may not only from the suppression of the oxygen chemisorption in the surface, but also from the freeze-out effect of the radiation-induced defects.