The invention provides an energy-saving device for an electronic product. The energy-saving device comprises a primary battery, a first storage battery, an electric energy switching device, a backlight mirror, keys, a light-emitting board, a compression spring piece, a second storage battery, a relay, a printed circuit board, a single chip microcomputer, an analog-to-digital converter, a temperature sensor and a fan, and the upper end of the primary battery is connected with the first storage battery and the electric energy switching device. By the design, mixed use of traditional electric power and new energy is realized, the backlight mirror is mounted at the front end of the light-emitting board, the keys are mounted at the front end of the light-emitting board, the compression spring piece is assembled at the rear end of the light-emitting board, and the second storage battery is arranged at the rear end of the compression spring piece. According to the design, the keys are illuminated, the single chip microcomputer and the analog-to-digital converter are welded on the printed circuit board, the upper end of the single chip microcomputer is connected with the temperature sensor, the fan is assembled at the upper end of the temperature sensor, and an intelligent cooling function is achieved. The energy-saving device is convenient to use, good in cooling effect and stability and high in reliability, mixed energy can be shared, and the keys can be brightened.