The invention relates to a high-flexibility halogen-free phosphorus-free epoxy resin composition and a flexible copper-clad plate prepared by using the same. The high-flexibility halogen-free phosphorus-free epoxy resin composition comprises flexible benzoxazinyl resin, silicon-containing epoxy resin, synthetic rubber, acrylate modified epoxy resin, nitrogen fire retardants, aromatic amine curingagents, imidazoles curing accelerators, antioxygen, an ion trapping agent, inorganic filling and a solvent. The flexible copper-clad plate prepared by using the high-flexibility halogen-free phosphorus-free epoxy resin composition comprises a polyimide insulating film, a high-flexibility halogen-free phosphorus-free epoxy resin composition coating coated on the polyimide insulating film, and a copper foil pressed on the high-flexibility halogen-free phosphorus-free epoxy resin composition coating. The high-flexibility halogen-free phosphorus-free epoxy resin composition does not contain halogen and phosphorus, has excellent flexibility; and the flexible copper-clad plate prepared by using the composition has excellent flexibility, heat resistance and processing property, and the fire resistance reaches the UL94 VTM-0 level.