Abstract: Biodiversity is an ecological complex formed by organisms and their environment, and a synthesis of various ecological processes related to biodiversity. Ecosystems include ecosystem characteristics, ecosystem products and ecosystem services. Changes in biodiversity affect ecosystem functions. The unprecedented loss of biodiversity has led to a lot of researches on the relationship between biodiversity and ecosystem functions. This paper summarized the theoretical formation and development of biodiversity and ecosystem functions since the beginning of the study, and the research methods at various stages.