Objective  Biodiversity conservation remains a hot topic in the arena of life science. Measurement of species evenness, a significant indicator of ecosystem stability, constitutes an integral part of biodiversity measurement . The evenness of species abundance is an objective indicator to measure the evenness of species in a real community. It is an effective way to characterize the evenness of species distribution to measure the difference between the evenness of species abundance and the evenness of species distribution in a real community.

  Method  In this study, a method for measuring species abundance distribution evenness (SE) is proposed on the basis of revising the classic genetic absolute distance equation. The data were collected from the fixed experimental plots in Jiaohe of Jilin Province, northeastern China and Xiaolongshan of Gansu Province in northwestern China.

  Result  The species evenness reflects the comparative relationship between the number of each species and the number of all species in the community, and reflects the balance of the number ratio (abundance) of each species in the community. The analysis of theoretical data and actual survey data showed that the modified genetic absolute distance equation could effectively distinguish the subtle differences of species abundance distribution, which improved the reliability of the application of genetic distance equation in comparing the differences of populations or communities.

  Conclusion  The species evenness measurement (SE) based on the modified genetic absolute distance equation can express the evenness of species abundance distribution in the community, and has a good analytical property. In the process of biodiversity analysis, we can analyze the causes of community diversity in combination with the comparative analysis of SE, which provides a theoretical basis for the formulation of targeted biodiversity conservation strategies.