Biodiversity includes four levels: genetic, species, ecosystem and landscape diversity. Recently, the concept of biological diversity gradually includes more levels of content such as biological area, culture and human diversity. The multi-level analysis and evaluation of biodiversity is an important research content and one of the difficulties in the field of ecology. Species diversity is a comprehensive reflection of species richness and distribution uniformity, reflecting community structure type, organization level, development stage, stability degree and habitat difference, reflecting the heterogeneity of biological community in composition, structure, function and dynamics. Landscape diversity and ecosystem diversity reflect landscape composition, species habitat range and shape, ecosystem structure, function and succession on a large scale. Biodiversity not only has the hierarchical structure of heredity, species, ecosystem and landscape, but also has the spatial scale effect. The spatial scale refers to the spatial measurement of the research object, which includes two aspects: amplitude and granularity. With the different spatial scale of evaluation, the performance of diversity index is different. The selection of scale affects the assessment of regional biodiversity. A region is rich in species diversity, is it also rich in other levels? Are the different levels of biodiversity consistent? Therefore, the analysis of genetic, species, ecosystem and landscape diversity at different scales in a region is of great significance for the theoretical research and application of biodiversity. In this paper, the related research literature at home and abroad is reviewed. From different levels of species, ecosystem and landscape, the assessment methods and scale effects of each level are analyzed, and the possible impacts of different assessment methods are summarized. Then, the coupling relationship between different levels of biodiversity is analyzed. Finally, the spatial scale effects of different levels of biodiversity are analyzed The coupling relationship between should and coupling is summarized, and the future research direction is prospected.