Siliceous rocks, as a type of chemical-sedimentary rocks widely distributed in geological history, have unique research value in the fields of palaeoenvironment, palaeoclimate and palaeontology. In recent years, with the increasing evidence of microbial participation in the process of siliceous mineral precipitation, the microbial silicification model has gradually attracted attention from scholars. However, the role of microorganisms in the process of siliceous mineral precipitation is still controversial. Previous studies generally believed that microorganisms play a "passive" role in siliceous mineral precipitation, that is, under the condition of supersaturated dissolved silicon concentration, microorganisms and their metabolites provide nucleation sites for siliceous mineral precipitation, and then through cation bridging, hydrogen bonding or direct electrostatic interactions, the siliceous minerals are precipitated on the surface of microorganisms. However, recent studies have found that even under the condition of unsaturated dissolved silicon concentration, the widely existed microorganisms in the Precambrian can also promote siliceous mineral precipitation through Mg2+ bridging, which means that the supersaturation of dissolved silicon is not a necessary condition for the formation of Precambrian siliceous rocks, further suggesting that the concentration of dissolved silicon in Precambrian seawater may have been overestimated and did not reach saturation.. Simultaneously, the expression of Silicon Transporters(SITs) during microbial silicification also suggests that the dissolved silicon concentration in Precambrian seawater may have begun to decrease as early as the Middle Proterozoic, earlier than the late Neoproterozoic-early Cambrian predicted by previous researchers. Therefore, microbial silicification plays a crucial role in the seawater silicon cycle model in geological history. However, the accurate assessment of the time of the decrease in dissolved silicon concentration and the specific dissolved silicon concentration are still urgent problems that need to be solved, and further exploration and more detailed research are worthwhile.