Weed presence within and around agricultural lands cause enormous loss of crop yield and quality. There are many methods for control of these plants. One of them is putting allelopathic in weed management programs. Allelopathic plant interactions can have either a harmful or beneficial effect and are generally evaluated by testing some physiologic mechanisms that result in the inhibition/stimulation of seed germination, plant growth and development due to the presence of another plant. Allelochemicals can be present in several parts of plants including roots, rhizomes, leaves, stems, pollen, seeds and flowers. Allelochemicals are released into the environment by root exudation, leaching from aboveground parts, and volatilisation and/or by decomposition of plant material. In order to study of allelopathic interaction of Phaseolus vulgaris and Datura stramunium Seedling using Equal-Compartment-Agar method the laboratory experiment was carried out in 2012 and faculty of agriculture of Isfahan University of Technology, Iran. In this method 400 ml glass beakers were filled with 40 ml of 0.4% water agar and then the agar surfaced divided into two equal compartments that were occupied separately with donor and receiver genotypes. This study was conducted in factorial form on completely randomized design with 3 replications and had two section for screening of allelopathy effect and response of twelve genotyps of bean follow as: Akhtar, darakhshan, naz, sayad, goli, ozbakestan, chin, pak, dorsa, khomein, talash and sedri and Datura stramunium was such as weed. The first experiment was evaluation of allelopathy potential of genotyps of bean on the Thorn-apple but the second one was to assay bean sensitivity under Thorn-apple allelochemicals. The results of the first study have proved khomein cultivar had most inhibitory on Datura stramunium accession , s root length but motivator on shoot length. While goli cultivar had the most stimulatory on Datura stramunium . In the second experiment, the growth of Akhtar, darakhshan, naz, sayad, goli, chin, pak, dorsa, talash and sedri have been prevented under Datura stramunium allelochemical. Khomein and Ozbakestan had no significant response to Datura stramunium allelochemicals, as a matter of fact these cultivars were resistance. Among bean cultivars studied, khomein was the strongest inhibitor in Datura s. growth and most telorance to Datura s. allelochemicals. Key words: Phaseolus vulgaris, Datura stramunium , ECAM, Allelopathy , growth inhibitory and stimulatory