An experiment was done during Kharif 2008 and 2009 at BCKV, Kalyani to study the weed control efficiency of herbicide as well as its effect on soil microorganisms including urease enzyme in Soybean crop field. Dominent weeds were: Echinochloa colona, Eleusine indica, Dactyloctenium aegyptium, Digitaria sanguinalis, Cyperus rotundus, Euphorbia hirta, Digera arvensis, Physalis minima, Phyllanthus niruri, Alternanthera philoxeroides and Amaranthus viridis. The treatment UPH-203 100 g/ha  + Na-acifluorfen 10% SL 206.2 g/ha was found best for efficient weed control as well as safe use for soil microflora including urease enzyme activity among all the treatments even in comparison to hand weeding treatment.