The invention discloses a bacillus amyloliquefaciens D2WM as well as a preparation method and application of bacillus amyloliquefaciens D2WM. The bacillus amyloliquefaciens D2WM comprises the steps of A, bacillus separation and purification, namely collecting after inoculating a slope; B, preliminary screening of bacillus, namely sequentially selecting strains having antagonistic effects on Erwinia and camellia oleifera diseases by using a point connection method and a plate confrontation method; and C, secondary screening of bacillus, namely culturing the preliminarily-screened strains with the antagonistic effects in an LB liquid culture medium by using a cup-plate method, and screening the strains simultaneously having the antagonistic effects on main diseases of Erwinia and camellia oleifera through an antagonistic bacterium fermentation liquid and sterile filtrate. When being applied to preparation of drugs for treating or preventing soft rot of vegetables and camellia oleifera diseases, the bacillus amyloliquefaciens has a broad-spectrum antagonistic effect, high in growth speed, capable of efficiently antagonizing anthracnose of camellia oleifera, leaf spot diseases of camellia oleifera, black spot of camellia oleifera, canker of camellia oleifera and various diseases and remarkable in antibacterial effect, the culture time for general bacteria and fungi is greatly shortened, and the production cost is reduced.