The invention provides an automatic control system for a shiitake mushroom culture room. The automatic control system comprises a master control upper computer, a PLC air conditioner controller, an air conditioner terminal, an ABB frequency converter, a CO2 transmitter, a fresh air valve and an air return valve. By setting various parameters on a touch screen, other terminal equipment such as an air conditioning unit, the frequency converter, the fresh air valve and the air return valve can be controlled, and aiming at the problem that the temperature of the room is not uniform, automatic turbulent flow can be achieved according to the temperature difference between the upper temperature and the lower temperature of the room, and regular turbulent flow can also be achieved. In order to solve the problem that a large amount of CO2 can be generated in the cultivation period of shiitake mushroom sticks, the CO2 concentration is detected, the fresh air valve, the air return valve, an exhaust fan and the like are automatically started according to set values, fresh air is automatically exchanged, high-concentration CO2 in the room is discharged outdoors, a timing fresh air exchange function can also be started, and fresh air is exchanged once every certain time. The automatic control system has an automatic air cooling function, if the environment temperature is far lower than the indoor temperature, equipment can be automatically converted into an air cooling mode, and therefore a large amount of energy is saved.