The invention discloses a resin composition. The resin composition is composed of, by weight part of organic solid, (A) 50-100 parts of epoxy resin, (B) 1-50 parts of flexible long-chain resin, (C) 2-100 parts of epoxy resin curing resin, and (D) 0.1-100 parts of flexible long-chain resin curing agent, wherein the flexible long-chain resin is one or more selected from polyvinyl alcohol phosphate,modified polyvinyl alcohol phosphate and polyhydroxyl polysiloxane resin phosphate; the flexible long-chain resin curing agent is one or more selected from isocyanate, modified isocyanate, isocyanate-terminated polyurethane prepolymer, isocyanate-terminated organosilicone prepolymer, boric acid, and borax. The resin composition can form a flexible long-chain resin crosslinking system during a recession stage of curing of an epoxy curing system, thereby endowing the entire resin composition system with very low resin overflow, and further solving the problems existing in prepregs in the prior art like cut powder due to power tenacity, and high resin overflow.