Abstract: Microorganisms can promote the dissolution of silicates by direct and indirect mechanisms. The contribution of both mechanisms to the mineral dissolution varies with the growth stage of microorganisms. By employing microfiltration membrane, this research tried to illustrate the contributions of these two mechanisms to dissolution of microperthite. The results showed that during 96 hours， culturing, Paenibacillus polymyxa and its metabolites can promote dissolving microperthite both by direct and indirect mechanisms. The direct mechanism can promote releasing Al, but has little effect on K and Si， which are considered to be mainly released by indirect mechanism. Direct and indirect mechanisms both show intense effects in stationary and dead phases. During mineral dissolution, consumption of bacteria growth and complexation of bacteria and metabolites are also important factors influencing the concentration of elements. Furthermore, the synergetic effect complicates the ion concentrations.