Numerical indices of diversity, in their entirety, do not provide a complete description of distribution and richness of species. Therefore, parametric indices should be also considered in studying of plant communities. In this regard, the indices of species richness, evenness and diversity related to the ecological sites of Cher mountainous rangelands of Urmia were calculated. The diversity profiles and rank-abundance species curves related to each of the sites were plotted and finally species diversity distribution models were fitted to each of data set using the Goodness-of-fit test and then best model was selected. There was no significant difference in terms of numerical indices among sites, but each of the indicators showed one of the sites be more diverse and made it difficult to distinguish the ecological site with high diversity. The difficulty of interpreting results considering the curves of diversity profile and rank abundance-species was also observable and the pattern of species distribution could not be understood. Therefore, surveying diversity using speciesabundance distribution models and fitting the data with current species distribution models was carried out. The results indicated that Log-normal model can be fitted to all the types with moderate grazing intensity (sites far from resting points). based on the results considering to the proper grazing intensity could conserve the plant diversity.