The invention discloses an energy recovery device among islands. The energy recovery device comprises a support plate, a sliding block, a sliding rail, a first screw rod, a floating ball, a cylinder,a limiting block, a support rod, a canvas bag, a second screw rod, a second screw nut, a bearing bracket, a one-way bearing, a flywheel, a gearbox, an electric generator, a connecting rod and a firstscrew nut, wherein the floating ball is mounted below the first screw nut; the first screw nut is mounted on the first screw rod; the left and right sides of the first screw rod are mounted on the bearing bracket; the connecting rod is mounted on the first screw nut; the sliding block is mounted on the connecting rod and on the sliding rail; and the left and right sides of the sliding rail are mounted on the bearing bracket. The energy recovery device has the advantages of utilizing the wind energy and wave energy among the islands.