The aim of this study was to survey the effective environmental factors on distribution of plant communities as one of the most important structure in semi-arid rangelands via field visits and various environmental factors measurements. However, various plant communities was studied in some part of kamyaran rangelands in about 10000 ha within different characteristics (altitudes and slopes), in each community 4 transects established with 300m length. 15 plots (1m2) established along each transect in 20 meter distances. The kind and the amount of existing species and the percentage of vegetation cover were determined in each plot. Various soil parameters such as physical factors (soil depths, soil texture) and chemical factors such as amount acidity, organic matter, electrical conductivity, lime and nitrogen were also measured. Soil and plant data were analyzed with multivariate analyzing, principal component analyzing (PCA). The results showed that among environmental factors, 5 factors including clay, sand, nitrogen, slope and altitude have the highest correlation with principal components and are the most effective influencing factors on plant communities’ distribution in semi-arid rangelands.