To study species diversity and its variation during a period of time 4 range sites were selected in Isfahan province. These sites were studied by Isfahan Research Center For Agriculture and Natural Resources and 10years of data was available for two Steppe sites ( Khondab, Golpayegan and Shadian, Shahreza ) and 6 years of data was available for two Semi-Steppe sites (Vardasht, Semirom and Akhche, Fereydonshahr ). Index of species richness was calculated for these sites. Heterogeneity indices ( Simpson diversity, Shannon-wiener, Hill , Hill , Brillouin, MCIntosh,, Manhinick and indices ) and evenness indices ( Simpson, Camargo, Smith Wilson and modified Nee ) were calculated for each site during study period. Kolmogorov-Smirnow ( K-S ) test indicated that there were significant ( ? = 10% ) differences between species diversity of two Semi-Steppe sites during 6 years of study. Similarly there were significant differences ( ? = 10% ) between diversity of two steppe sites in all 10 years of study except years 2002 and 2006. Index selection should be based on management goals. For vegetation analysi and are appropriate indices. In steppe sites with higher dominance it is better to use while in Semi-Steppe sites with higher diversity gives better results. To study evenness in both zones Smith Wilson index is suitable. Counting numbers of species in steppe zone is efficient for species richness, while in Semi-steppe zone other methods such as species-area curve, rarefaction, Jackknife, bootstrap are suitable. According to Canonical Correspondence Analysis ( CCA) precipitation, OM% and stipness were highly correlated, where as temperature and precipitation had high negative correlation. Diversity had high positive correlation with OM% and precipitation and number of species had high positive correlation, with precipitation. Key words ecies diversity, Species richness, Heterogeneity, Evenness