The biodiversity is the key concept of ecology and its understanding and analysis is crucial for any ecological research. There are three main approaches to answer the questions on biodiversity: diversity indices, species abundance models and multivariate analysis of biological communities. The analysis of biodiversity data is a very complex task and requires adopting several various methods of their analysis (diversity indices, species abundance models, multivariate analysis). Only the combination of methods supported by the ecological knowledge of species and underlying processes is the correct way of biodiversity data analysis.