The invention relates to the technical fields of photoelectricity and chemical industry, in particular to a low-stress epoxy/organic silicon/POSS nano hybrid material, and a preparation method and application thereof. The epoxy/organic silicon/POSS nano hybrid material comprises (a) an epoxy resin, (b) a polyorganosiloxane, (c) a cage-type polysilsesquioxane (POSS), (d) an epoxy hardener, (e) non-essential silane oxycompound and (f) non-essential assistants, wherein the polyorganosiloxane contains epoxy groups and silane oxygen groups. The cured nano hybrid system has excellent reticular cross-linked structure and does not have microphase separation. The epoxy/organic silicon/POSS nano hybrid material has the advantages of high mechanical strength, favorable heat resistance, favorable cohesive property, high chemical stability, favorable ultraviolet aging resistance, favorable optical transparency and other excellent properties, has the functions of low internal stress and pressure buffer, and can be used as an LED packaging material, optical protection material, circuit protection coating material, adhesive paint and the like.