In order to evaluate control effect of Bacillus vallismortis on gray mold of antagonistic bacterium
strain NBIF-001，this paper determined its inhibition activity to the pathogen of Botrytis cinerea by dual culture
method combined with optical microscope observation；and studied its controlling effects on cucumber leaf grey
mold and tomato fruit grey mold by in vitro tissue test．The results showed that the strain NBIF-001 had high
inhibition activity in dual culture．Optical microscope study revealed deformation of hyphal and enlargement
of cytoplasmic vacuoles．In vitro tissue test shew that NBIF-001 exhibited better biological control effect on
cucumber and tomato gray mold．The control effect reached 85.91% and 72.52%， respectively．