Infrared automatic control switch was traditionally adopted in purification of dust prevention water curtain in complete section of coal mine roadway. Desensitization of switch was caused by difficult conditions and its promotion was hard to push in coal mining industry on the basis of high cost, short life, unavailable maintenance and poor effect of lasting and utility. After research, manual bilateral switch device which had the same effect of infrared automatic control dust spray switch was made. The device not only had advantages of low cost and convenient making, but also low spoilage, simple maintenance and low maintenance cost.