Abstract: The solid-state desilication kinetics of silicon manganese powder and Brazil manganese powder was investigated by microwave heating and conventional heating. During the two processes, Brazil manganese powder which reacted with silicon in silicon manganese was used as the desilication agent. The mixture was heated up to different temperatures and preserved heat for some time by microwave heating and conventional heating, respectively. The silicon content of desilication materials was measured and the apparent activation energy of desilication reaction was calculated. The results show that the single raw material and the mixture could be heated up in the microwave field in a short time. The desilication rate increases with the increase of heating temperature and holding time by both heating methods. The desilication rate and the reaction rate under the microwave field are significantly higher than those by conventional heating. Microwave heating can increase the rate of solid phase desilication. The restrictive step of solid-state desilication kinetics of silicon manganese powder and Brazil manganese powders by microwave heating is the diffusion step. The apparent activation energy of desilication reaction under the microwave field is 102.93 kJ·mol^-1, but the apparent activation energy of desilication reaction by conventional heating is 180 kJ·mol^-1. The microwave heating field can improve the kinetics condition of solid phase desilication, increase the reaction rate of solid phase desilication and reduce the activation energy of desilication reaction.