Based on the eight bacteria strains with potential bio-control activities obtained by our research group in the early stage, this study screens the bioactive strains against F. graminearum, and initially explores the substantial basis of their bio-control activities. Preliminary screening of the strains via the plate confrontation method showed that two strains of Bacillus amyloliquefaciens DEB-2 and D₁ had high antifungal activities with the rates of 51.32%and 49.48% respectively. The fermentation broth of DEB-2 had significantly greater antifungal activities than that of D₁（P＜0.01）. The genetic stabilities of the strains and the sensitivities of the fermentation broth of the strains to ultraviolet radiation revealed that both DEB-2 and D₁ had high stabilities with no significant difference. However, in terms of pH and temperature stabilities, the stabilities of DEB-2 were significantly higher than that of D₁（P＜0.01）.DEB-2 was not affected by pH change, while D₁ decreased in activity with pH increasing. At 121 ℃, the antifungal activities of DEB-2 fermentation broth remained 62.35%, while D₁ dropped to 15.74%. The bioassay results also showed that the control effects of DEB-2 was significantly higher（P＜0.01） than commercial bio-control agent Bacillus subtilis strain. Therefore, DEB-2 was selected as a candidate strain for biological control of wheat head blight. In order to explore the substantial basis of DEB-2 bioactivity, a cyclic-（L-phenylalanine-L-proline） was found via GC-MS analysis of the bioactive ethyl acetate layer, which was reported to have a relatively strong antifungal effect on wheat head blight. It can be speculated that DEB-2 had a antifungal effect against F. graminearum, which may be related to the production of cyclo-（L-phenylalanine-L-proline）.