Obesity has become an increasingly severe problem in modern society. Thepresentapplication discloses methods for making obesity animal models, and theapplication of suchobesity animal models on screening microorganisms, compounds, compositions,drugs, food,formulations or recipes, medicines, nutritional supplements, health careproducts, or beveragesfor their role in causing, preventing or treating the obesity. A method forestablishing an obesitymouse model is disclosed, comprising, inoculating a germ-free mouse with anEnterobactercloacae B29 having a 16S rRNA gene to provide an inoculated mouse, wherein thesequence ofthe 16S rRNA gene is at least 95% identical to SEQ ID NO.1； while feeding theinoculatedmouse with a diet having 34.9 wt% of fat content for a period of time toprovide an obesitymouse model, wherein the obesity mouse model manifests a metabolic syndrome,theEnterobacter cloacae B29 is capable of colonizing in the germ-free mouse'sgut.
