The invention belongs to the technical field of chemical industry and photoelectricity, and in particular relates to a high-heat-resistant POSS/epoxy nanometer hybrid material and a preparation method and application thereof. The high-heat-resistant POSS/epoxy nanometer hybrid material comprises (a) at least one epoxy resin, (b) at least one polyhedral oligomeric silsesquioxane (POSS), (c) at least one acidic curing agent, (d) unnecessary organosilane, and (e) an unnecessary auxiliary agent. The POSS/epoxy nanometer hybrid material prepared by the method does not have a phase separation phenomenon, has the characteristics of the epoxy resin such as high caking property, mechanical strength, shearing strength and processability, and has the characteristics of the POSS such as high heat resistance, insulating property, elasticity, ageing resistance and transparency; the production and preparation process is simple, and easy to control; a solvent is not used in the production process; and the method is an environmental-friendly and energy-saving method for synthesizing the POSS/epoxy nanometer hybrid material. The POSS/epoxy nanometer hybrid material is used for an adhesive, an LED packaging material, a photoelectric conversion material, an insulating material, a coating material, a circuit protection material, an optical protection material and the like.