Knowledge of plants distribution patterns in each region is one of the essential and preliminary perquisites to vegetation measurement and investigation. In order to investigate and analysis of density and also to determine distribution pattern measurement methods, a study site with 4 replications in Fereydunshahr county of Isfahan province by dominant vegetation type of Astragalus verus - Bromus tomentellus was selected. In each site,(a 5000 area in 50*100 m dimension), the real density value was obtained by counting all individuals of target species. In each site sampling was carried out as random-systematic pattern. In each replication, five 100 m transects were established and some points were selected as random given to each method required sample and density measurement methods (2 quadrate, closest individual, morisita's closest individual, nearest neghbour, random pairs, point- center quarter, wandering quarter, wandering angle, Diggle's distance point, square T- byte, angular, ordered method (the second, third and fourth closest individual) were determined along with the methods for determination of distribution pattern based on three distance indices (Hopkines Index, Pielou Index, Johnson and Zimer Index, Eberhart Index, Holgate Index, Hines Index, T square Index), quadratic ones (Green's Index, Morisita's Index,, Lyoid's Index of patchiness, dispersion Index , standardized morisita Index) and point distribution analysis. The difference between density measurements approaches to control ones (stands counting) was evaluated by means comparison test LSD. As for species A.verus and B.tomentellus the closest estimation to controls were the nearest neighbor and order (the second nearest individual) respectively. The methods wondering quarter, quadratic, wandering angle and regular angle indicated significant difference to control ones. The largest and least sample size is related to regular angle and wandering quarter methods respectively. The angle and T square methods had the highest and least measurement times among others. In terms of precision, the methods nearest neighbor had the highest and methods wandering angle and wandering quarters indicated the least precision. Because there was not possible to measure all stands coordinates in each site while point analysis, a reference area by 225 (15*15m) was selected as random and spatial coordinates for A.verus and B.tomentellus were recorded. Results showed that distribution of species A.verus and B. tomentellus follows random pattern due to environment homogeneity and plants selective behavior pattern. Among distance indices, hapkines and pielou offered more appropriate and realistic results. Out of 12 distribution pattern indices, the T square and green ones had the highest precision and except Green's Index, distance indices had the higher precision than quadratic ones. Correlation type and value between two species Astragalus verus and Bromus tomentellus were evaluated using two methods Ci square and bi-variables point pattern analysis, implying to positive correlation between shrub species A.verus and grass of B.tomentellus. Keywords : density estimation method, plants distribution pattern, sample size, correlation, Fereydunshahr County, Isfahan province