Abstract: Spacecraft charging due to irradiation by radioactive rays and plasma environment can cause serious problems to the safety and reliability of spacecraft on the orbit. The secondary electron emission（ SEE） yield of space materials is one of important parameters relative to the spacecraft surface charging level,it is also important for prediction of satellite surface charging and selection of surface materials in the design against spacecraft charging. Based on Monte Carlos simulation method,this paper investigates the theoretical process of generation,transfer and escape of secondary electrons as a function of the surface potential of the spacecraft,and finally the paper present a mathematical model to calculate the secondary electron emission yield. The results indicate that this calculation method can preferably fit the trend of secondary electron emission yield varies with primary electron energy,and the work can provide the perspective of the spacecraft charging problem.