A device for internal cooling and pressurization of rotary engine, comprising: a mechanical charger, a charger outlet tube, a core cooling intake tube, an engine air intake tube, a first valve, a second valve, and a third valve. The mechanical charger is mounted in a ventilated place. The charger outlet tube is used to dispense air, and the charger outlet tube has two sides, with one side coupled to the mechanical charger. The core cooling intake tube is connected to another side of the charger outlet tube, and is used to dispense air. The engine air intake tube is connected to another side of the charger outlet tube. The device for cooling and pressurization of rotary engine is capable of achieving improved cooling and performance of rotary engine, through switching a plurality of valves, in automatic control manner and/or in remote control manner.