The bio_desulfurization of coal technology is one of the important research topics both at present and in future. In this study, the silicate bacteria growing in media that contained high_sulfur coal were used to remove sulfur in coal. The results show that the silicate bacteria could be used to desulfurize high_sulfur coal. Total sulfur content was reduced from 5.45％ to 3.45％ after the treatment. The total sulfur removal rate reached 36.70％, in which the effective removal rate reached 9.91％. Compared with the static cultivation manner for silicate bacteria, the shake cultivation manner shows much better desulfurizing effect on coal. The silicate bacteria cultured in nitrogen_containing culture media show better desulfurization effect than those cultured in nitrogen_free media. Preliminary data obtained indicate that the silicate bacteria not only cause oxidation of sulfide iron_sulfur in coal, but also result in absorption and metabolism of the organic sulfur and inorganic sulfur in coal. It is suggested that there exist two mechanisms for coal desulfurization by the silicate bacteria: ① silicate bacteria and their metabolites result in sulfur oxidation in coal; ② the sulfur in coal experiences absorption and metabolic conversion by the silicate bacteria. There are two kinds of mechanisms which have the effect on all forms of sulfur in the coal sample. The study also implies that silicate bacteria have the latent application potential in the study of coal desulfurization.