In this paper,the charge simulation method (CSM) and the boundary element method (BEM) that are two ways to calculate the high-voltage substation's industrial-frequency electric field are introduced.For these two methods have their own shortcomings,a new method is put forward which combines the CSM with the BEM. BEM is used to solve the electric field generated by the surface charge of the switchgear.As the various components have different nature,indirect boundary integral equation of the grounded metal pi...