The invention relates to the technical field of irritation volatile solution preparation devices, and discloses an automatic auxiliary device for a thermal power plant prepared irritation volatile solution and a using method thereof. The automatic auxiliary device comprises an auxiliary medicament box, an air exhaust device, a medicament outlet main pipe, at least one medicament inlet branch pipeand solution medicament boxes, wherein the quantity of the solution medicament boxes is matched with that of the medicament inlet branch pipes; the auxiliary medicament box is a fully-closed box body;and the top of the outer side of the auxiliary medicament box is communicated with a medicament filling pipe and an exhaust pipe respectively. The automatic auxiliary device is reasonable and compactin structure and convenient to use, volatilized irritant gas can be discharged in time, the damage and influence of mass volatile, irritant and carcinogenic gas of the irritant and volatile solutionon the physical and psychological health of people are avoided, quick, accurate, efficient and successful preparation of the solution with a required solution can also be realized, and the requirementof production is met; and the device is small in equipment volume, simple in operation, convenient and flexible and high in degree of automation, is applicable to production field, and has extremelyhigh practical values on site.