Provided are an exosome preparation formed by secretion by a mast cell cultured in vitro, a preparation method of an exosome therein, an exosome containing FcεRI protein on an outer surface thereof and in a substantially unbound state, and uses of the exosome preparation or exosome in a method for inhibiting mast cell activation in vitro and in preparing a drug for treating an IgE-mediated disease.
