AbstractThe conservation of boidiversity is faced with two basic problems : how to determine biodiversity measurements and how to conserve biodiversity. Based on species concept , the traditional ways for biodiversity measurements are to determine different kinds of biodiversity indices by using ecological and geographical approaches. These measurements depend on the size of sample areas in investigations and all species are valued equally in taxonomy. The phylogenetic diversity measurements of biodiversity are based on the theories and methods of phylogenetics and genetics and can determine contribution of a species in a taxon to the taxic diversity . But this approach is too complicated and can be used in conservation only when phylogenetic and genetic data are much complete. It is suggested that combination of species viability approach and the phylogenetic diversity measurements will contribute to determining the priority of species and ecosystem conservation