Microbial nitrification is a key process of nitrogen cycling in ecosystems.It is not only related to the occurrence of environmental problems such as acid rain,greenhouse gases and water eutrophication,but also plays an important role in the nutrient conversion of nitrogen in soil and it is closely related with human life.The microbes which are involved in soil nitrification include bacteria,archaea and fungi.According to their different types of energy metabolism,these microorganisms use different enzymes to carry out nitrification by different mechanisms.In this paper,the microbial groups that are reported to be autotrophic(classical autotrophic nitrification and full ammoxidation)and heterotrophic nitrification in ecosystems are reviewed.The key enzymes of nitrification and their coding gene types are summarized,their distribution characteristics in ecosystems are diverse,and its frontier molecular ecology research methods are reviewed.At the same time,the prospect of different types of nitrifying microorganisms in the future is put forward,in order to provide a reference for the systematic study of nitrifying microorganisms in soil ecosystem.