Bi4Si3O12 powders are prepared by template -hydrothermal used Bi4Si3O12 as a template made by molten-salt method. The phase composition and morphological characteristics of BSO nanoparticles were analyzed and observed by X-ray diffraction and transmission scanning electron microscopy. The results show that with the salt content of 50wt%, calcination temperature 770°C, it can form a high purity Bi4Si3O12 template. A single Bi4Si3O12 phase can be obtained by template –hydrothermal, with template addition 30wt%, the reaction temperature 240°C, holding time for 24h, and prolonging the reaction time is conducive to Bi4Si3O12 grain growth. The powders have a good dispersion, and size of particles is about 10μm or so, and show a columnar shape.