Disclosed in the invention is an energy-harvesting-circuit-based piezoelectric-electromagnetic composite energy harvesting device. The invention relates to a piezoelectric-electromagnetic composite energy harvesting device capable of improving an output power, which belongs to the technical field of the new energy and power generation. The piezoelectric-electromagnetic composite energy harvesting device comprises a piezoelectric-electromagnetic composite energy harvesting device body and an energy collection circuit. The piezoelectric-electromagnetic composite energy harvesting device body consists of a housing, a coil, an upper permanent magnet, a piezoelectric ceramic material, a foundation beam, a tapered permanent magnet, a lower permanent magnet, an upper electrode, a piezoelectric plate, a lower electrode, a left piezoelectric plate upper electrode lead, a right piezoelectric plate upper electrode lead. The energy collection circuit includes an electromagnetic energy harvesting device energy collection circuit, a piezoelectric energy harvesting device energy collection circuit, and a charging circuit for realizing composite charging and preventing current returning. According to the invention, conversion from an alternating current to a direct current is realized; the output power supply is improved for a load. The energy harvesting device has advantages of green and pollution-free effects, high energy density, shortened charging time, high reliability, high environment adaptability, convenient operation control, and low maintenance cost and the like.