The invention relates to the technical field of engines, in particular to an energy-saving gas introduction device of an engine. The energy-saving gas introduction device of the engine comprises a container bottle, a gas inlet pipe, a gas outlet pipe and a gas transmission pipe, wherein a liquid additive is filled in the container bottle; a heat preservation box is arranged outside the container bottle; a protective cover for preventing liquid from being splashed out is arranged above the liquid level of the liquid additive; a gas generation piece is arranged at the gas outlet of the gas inlet pipe; a needle valve for one-way conduction of the gas is arranged on the gas inlet pipe; and the gas outlet of the gas outlet pipe is communicated with an intake manifold of the engine and/or a ventilating pipe of the engine through the gas transmission pipe. The energy-saving gas introduction device of the engine is used together with the liquid additive, so fuel oil can be combusted fully. The energy-saving gas introduction device of the engine can run normally at various temperatures, so the working efficiency is improved greatly, the liquid can be prevented from being splashed into the engine, and damages caused by the liquid splashed into the engine can be avoided.