1.Under the condition of pure culture,Trifluralin,Linuron and Lasso(10-50 ppm) showed sensitive inhibitory effect on the growth of bacteria,while Amiben had no this effect.Azotobacters and Saccharomycetes had high resistibility to herbicides.Nodule bacteria of soybean and green manure crops could be grow well on Trifluralin agar plate in which the concentration was 5-20 times as high as that in the fields.The growth of actinomycetes and majority of fungi was inhibited strongly by Lasso and Linuron.Trifluralin and Amiben had inhibitory effect only on a few actinomycetes and fungi.The formation of actinomycete conidiospores was inhibited by most of herbicides under the condition of low concentration.