In order to investigate the optical and physical properties and stability of the Mie scattering diffuser(MSD) in spatial environment, some reflective properties including the directional hemisphere reflectance (DHR), the bidirectional reflectance distribution function (BRDF) and the resistivity were measured. The results show that the reflectance achieves 80% at the band of 350～2000 nm, the differences of the reflectance is less than 0.024 per hundred nm. The variations rate of BRDF(10°～75°) is less than 5.2×10－4 at the band of 900 nm. The resistivity of MSD is about 1012{\\mkern 1mu}Ω·cm, it reduces the internal charging hazards to a great extent in the space. The experiment of radiation test shows that the MSD has the characteristic of stability of orbit radiation. Therefore, MSD can satisfy the requirements for space applications of use of the geosychronous orbit satellites.