The present invention relates to a novel epoxy compound, a method for preparing same, a composition and cured product comprising same, and use thereof, wherein the compound shows excellent heat-resistant properties—specifically, a low thermal expansion property and a high glass transition temperature (including Tg-less which does not show a glass transition temperature), a flame retardant property and processability—specifically, a viscosity-control property, does not require a separate silane coupling agent, and has improved brittleness in a composite. According to one aspect of the present invention, provided are: an epoxy compound having at least one non-reactive silyl group, alkenyl group or combination thereof together with at least two epoxy groups and at least one alkoxysilyl group; a method for preparing the epoxy compound through alkoxysilylation and alkylsilylation; an epoxy composition comprising same; and a cured product.