The possibility of biological control of the Fusarium graminearum, the causal agent of wheat crown rot and seedling blight bybacterial antagonistic strains were evaluated. Healthy spike of wheat and soil samples were collected from Mazandaran and Golestan provinces. A total of, 312 bacterial strains (G+ve & G-ve) were isolated and then the inhibition zones of bacterial strains on mycellium growth of the pathogen were determinate. According to the phenotypic features and electrophoretic protein patterns, representatives of bacterial strains were identified as a Pseudomonas fluorescens biov. I, Bacillus subtilis strains 53 & 71and Streptomyces sp. In vitro conditions, the effect of bacterial exudates, volatiles substance and thiophanat-methyl on the prevention of mycelial growth and its effects were studied on morphology of disease agent. The results showed that the exudates strain 32 of P.fluorescens biov I. was more effective with 2.54 cm inhibition zone than to other strains. All strains were able to produce volatile substances, but the strain53 of B. subtilis was better than other treatments and have reduced 47.77% of the mycelial growth of disease agent fungus.Bacterial exudates and volatile substances of antagonist strains caused deformation and swelling in mycelial disease agent fungus. The comparison between the 50 ppm concentrate of thiophanat- methyl and bacterial exudates showed that antagonists have a better effect on preventing growth of the disease agent, so that B. subtilis strain 71, P. fluorescens biovI strain32 and thiophanat-methyl have reduced respectively 85.74%, 97.12% & 97.1% of the mycelial growth of disease agent. The results of greenhouse studies showed that the effect of antagonists were significant and seed and soil treatments by strain 71 of B. subtilis and Streptomyces sp. strain 3 in the presence of the disease agent leads to increase plant height, dry and fresh weight of shoot and root