Understanding the plant species behavior in response to various ecological and management factors can assist range managers to select the best management practices. This study aimed to evaluate the effects of environmental and management factors on vegetation distribution in Zayanderood dam watershed station in Chadegan- Isfahan, where some parts of the study area have rested from grazing over the past 20 years. Stratified random sampling technique was used to collect the vegetation and soil characteristics data. The study area was stratified based on the various management types (grazed and non-grazed areas) and slope directions, and samples were collected randomly in each layer. Four perpendiculars transects with 500 meters length were established along the management and environmental gradients. One transect was established in the un-grazed area and another transect was placed in the lightly grazed area. Two other established transects were covered both grazed and un-grazed areas. Plots were placed along the established transects, covering all the environmental and managerial condition of the study area and plant cover percentage and density were then measured. Plot size was determined based on the longest diameter of the canopy species (1 × 1.5 m ) in the study area. Sample size was also determined by statistical method. Fifteen plots were placed along each transect due to the extreme topography condition of the study area. The cover percentage and density of the perennial plant species were recorded in each plot. The management condition (un-grazed and slightly grazed), slope percentage, aspect, elevation from sea level, and the hillside shapes of the all studied plots were also recorded. Soil samples from the 0- 30 cm and 30- 60 cm of soil surface were collected from the center of 24 established plots randomly. The pH, electrical conductivity, sand, clay, silt, sodium, calcium, magnesium, phosphorus and potassium contents, organic matter, cation exchange capacity, calcium carbonate, gravel and soil saturated moisture of the collected samples were measured. Independent t-test was used to compare the density and vegetation cover of all perennial species between the grazed and un-grazed areas. Canonical Correspondence Analysis (CCA) and Multidimensional Scaling ( MDS ) was used to explore the relationships between environmental and management factors with the species distribution in CANOCO and PATN software. Cluster analysis was also used to group the studied plots. Simpson and Shannon diversity indices, Menhinic and Margalef species richness indices and Simpson evenness index were calculated and compared in the both areas. The parametric diversity models including geometric series, the series log, log-normal and broken stick were fitted to the collected plant species frequencies using PAST software. According to the results, the cover percentage and density of the perennial plant species in the un-grazed areas were increased significantly (?=5%). The results of parametric and non-parametric multivariate analysis indicated that the gravel percent, calcium carbonate, phosphorus soil contents, soil texture, cation exchange capacity and management types were the most important ecological and management factors to separate the identified plant species groups in the study area. Although diversity, richness and evenness of the un-grazed area were more than the grazed area, the diversity and evenness indices of the two areas were not significantly different. The richness indices were significantly different between the grazed and un-grazed areas. The log-normal model was the best fitted parametric diversity model indicating the presence of immature communities with relatively stable and moderate abundance of plant species. In conclusion, the long term resting from grazing resulted to more vegetation evenness and plant diversity and enhances the stability of this semi-arid rangeland ecosystem. Keywords : Range, Ordination, Cluster analysis, MDS method, Species diversity, Species richness, Evenness, Zayanderood dam watershed station