Abstract:Diatoms are one of the most widely-used bioindicators for water environment monitoring. In contrast, terrestrial diatoms are less investigated. As an important component of soil microorganisms, diatoms play an important role in soil biogeochemical cycles. The research history of soil diatoms can be divided into three stages, i.e. the initial period (1910s—1950s), the slow development period (1970s—1990s) and the rapid development period (2000s—). This study aims to explore biodiversity, geographical distribution and environmental significance of soil diatoms. At present, more than 300 soil diatom species have been identified, with high species richness of soil diatoms in the sub-Antarctic, Poland and Luxemburg. Soil diatoms can be broadly divided into three categories, including acidophilic, alkaliphilic and cosmopolitan species. Previous studies revealed that diatoms were sensitive to variations in soil environmental conditions, such as soil pH, humidity and organic matter content. Therefore, diatoms are a potential bioindicator of soil environmental changes. On the basis of standard analytical methods of soil diatoms, further studies are needed to strengthen taxonomy studies of soil diatoms, to compare diatom communities among different types of soils, and to explore global biogeography of soil diatoms. In addition, the role of diatoms in soil biogeochemical cycles is needed to be explored.