The invention relates to a device and a method thereof for realizing data sharing between single chip microcomputers in an electric energy quality detection device. The device comprises a first single chip microcomputer, a second single chip microcomputer and an SPI (Serial Peripheral Interface) Flash, wherein the first single chip microcomputer, the second single chip microcomputer and the SPI Flash are arranged in the electric energy quality detection device; the state output port of the first single chip microcomputer is connected to the state input port of the second single chip microcomputer; the state input port of the first single chip microcomputer is connected to the state output port of the second single chip microcomputer; after the SPI of the second single chip microcomputer is connected with the SPI of the first single chip microcomputer in parallel, the SPI of the second single chip microcomputer is connected to the SPI of the SPI Flash; and the SPI Flash is used as a data sharing cache of the first single chip microcomputer and the second single chip microcomputer. The device and the method can simply and effectively realize large data volume sharing between the two single chip microcomputers.