Abstract: The charge accumulation on satellite surface in substorm is not avoidable.Owing to the difference in physical characteristics between sur- face materials,the accumulation of charge will not be in equilibrium.How- ever,the potential difference no sooner establishes than the exchange of charge between surface and frame of satellite begins to decrease gradual- ly. The relationship among the change of potential difference,the surface potential value,the surface conductivity and the capacitance has been de- duced by means of establishing a physical model.Thus a mathematical model can be obtained.The analysis of charging state on a satellite surface can be realized by the mathematical model.

Key words: Satellite, Electric charge, Surface potential, Mathematical, model, Analyzing