Abstract: For the suppression of multipactor breakdown in the high-power components,a porous structure on the surface has been proposed for the reduction of secondary emission yield and the improvement of multipactor threshold. Emphasis is placed on the simulation analysis of the secondary emission properties of different metal materials and finishing conditions.First,an electromagnetic PIC(Particle in Cell) algorithm to force electrons in the predefined hexahedral meshes is established with the combination of the wave equations and the electron dynamics theory. Combined with the secondary electron emission theory,a simulation method of microwave components,has been implemented. Then,secondary electron emission data of metal samples under different finishing conditions have been measured based on the biased current method. Effects of secondary electron emission on multipactor have been analyzed. Simulation results of a typical microwave switch demonstrate the physical pictures of the development of electron multipacting at certain power level. Then,secondary emission properties of silver under different surface processing have been measured and the recorded multipactor thresholds have been simulated, which agree well with the experiments.