处于等离子体环境中的航天器的介质材料受到带电粒子的作用，表面将产生电位。对背面接地的介质材料，上表面将与接地背面形成电势差。当电势差达到一定阈值时将产生放电，表面充电电位对充放电效应影响至关重要。综合考虑等离子体中粒子的质量、温度及密度，介质材料的二次电子效应，体电流泄漏以及介质材料的运行速度等因素，基于气体动理论，利用粒子的麦克斯韦速度分布函数理论推导得出等离子体环境中背面接地介质材料表面充电电位一般表达式。讨论了地球同步轨道环境下，表面电位与等离子体环境及材料表面电阻等各个参数的关系，总结出等离子环境背面接地介质材料表面充电规律，为航天器介质材料静电防护设计提供一定的理论基础。

As a result of interaction between the spacecraft and the charged particles in plasma environment，the surface charging inevitability occurs. On the back grounded dielectric material，there exists a potential difference between the upper surface and the grounded back surface. The surface potential plays an important role in charging and discharging effects. Discharging occurs if the generated electric fields exceed the breakdown threshold. Taking a comprehensive consideration of the plasma particle’s mass，temperature and density，the secondary electron effects of the dielectric materials，body leakage current and the flight speed，a general expression for surface potential of back grounded dielectric material in plasma environment is derived using the formula of particle’s Maxwellian velocity distribution. Consequently，the dependences of the surface potential on each of the parameters are discussed concerning the geosynchronous orbit (GEO) environment，and some useful rules are summarized for the surface charging of back grounded dielectric material immersed in plasma. The method introduced here can facilitate the risk assessment for spacecraft surface charging and provide certain theoretical basis for spacecraft charging protection.