The invention discloses a controlling method for a workshop air conditioner. The controlling method comprises the following steps that after a command of a workshop control system is received through the Zigbee communication technique, the workshop temperature is adjusted to the set temperature, and the air conditioner turns to be in a dormant state; and current gas data of a workshop are detected through a gas sensor, whether the current gas data are within a proper gas data range of the workshop is judged, and if the current gas data are higher than the gas data range, a sterilization mode is started, otherwise a current working mode is maintained. By means of the controlling method, sterilization can be conducted in the dormant state of the air conditioner through temperature adjustment, intelligent control over the workshop environment temperature and sterilization are achieved, and the effect of saving energy and electricity is achieved.