Incessant and indiscriminate use of some agrochemicals in agricultural production has elicited fears of changes in microbial populations and the activities of individual species of micro-organisms. Present study was carried out to study the effect of three pesticides (Chloropyrifos (1L/200L.Water), Lambada cyhalothrin(50g/100L.Water) and Emamectin benzoate(120g/400LWater)) at field application rate on total population count of microorganism  in phasoulus vulgaris field . Also measured the sensitivity of some species,  bacteria (Rhizobium leguminosarum. And Bacillus thuringiensis) , fungi (Trichoderma harzianum and Trichoderma viridi) and actinomycetes (Streptomyces griseorubensand Streptomyces cavourensis at field and double application rate to these pesticides . Data indicated that, Chloropyrifos stimulated significantly the proliferation of all of the microorganism. Lambada-cyhalothrin decreased population of Bactria at 1 DAT (day after treatment) until 15 DAT and returned to increase at 21 DAT . For fungal population, the total count of the soil fungi was decreased after the addition of Lambada-cyhalothrin . Actinomycetes was also significantly inhibited during the period from 1 to 15 DAT by Lambada-cyhalothrin, and subsequently recovered to a similar level of control. Emamectin benzoate in general increased population of bacteria and actinomycetes and decreased population of fungi. Concerning the sensitivity study we found that , Chloropyrifos inhibited significantly the growth of the tested species at different rates with a positive correlation. Chloropyrifos was the most potent compound followed by Lambada-cyhalothrin while Emamectin benzoate did not happen any effect on tested species. For radical growth of T.harzianum and T. viridi   Chloropyrifos ,  Lambada-cyhalothrin and Emamectin benzoate showed  the same level in its impact on the bacteria and actinomycetes