The invention discloses a bacillus and application thereof, and belongs to the field of biological control. A bacillus strain is bacillus methylotrophicus C1, and a preservation number of the bacillus strain is GDMCC No.60046. The application includes that the bacillus can be used as a biological control strain to be applied to antagonistic crop pathogenic bacteria; the bacillus can be used as a lipopeptide and/or protein fermentation strain for inhibiting crop pathogenic bacteria; the bacillus can be used as a growth promotion strain to be applied to promoting growth of crops; the bacillus can be used as a fermentation strain for auxin. The bacillus and the application have the advantages that the strain has broad-spectrum antibacterial activity; lipopeptide substances with effects of inhibiting fusarium graminearum cannot be generated, but proteins with effects of inhibiting the fusarium graminearum can be generated; effects of promoting growth of corn can be realized by the strain C1, the root lengths and the stalk lengths of the corn of experiment groups are 3.15 and 3.05 times the root lengths and the stalk lengths of contrast groups respectively as compared with contrast, the root, stalk and seed weights of the corn of the experiment groups are 5.02, 4.33 and 1.4 times the root, stalk and seed weights of the contrast groups, and only little auxin can be generated by the strain C1.