The invention belongs to the technical field of biology and particularly relates to Bacillus tequilensis and an application thereof. The Bacillus tequilensis is named Bacillus tequilensis QX13, and the Bacillus tequilensis is collected in CGMCC (China General Microbiological Culture Collection Center) with collection number of CGMCC No.16618 in Beijing China on October 24, 2018. The strain has a remarkable inhibition effect on Sclerotium rolfsii as a pathogenic fungus of peony southern blight, can effectively control peony southern blight and has a remarkable inhibition effect on other plant diseases such as peony brown spot, tomato early blight, Chinese rose shoot blight or pepper phytophthora blight, besides, the strain is harmless to the ecological environment, cannot cause drug resistance of pathogens, is easy to store, facilitates industrial production and has good development and application prospects, and the culture conditions are simple.