The invention relates to a method for preparing a pesticide adjuvant by using electrostatic defogging liquid for producing AES (Alcohol Ether Sulfate). The method provided by the invention has the purposes that the electrostatic defogging liquid is recycled, wastes are turned into valuables, the application value is improved and the environment pressure is alleviated. According to the technical scheme, the method for preparing the pesticide adjuvant by using the electrostatic defogging liquid for producing AES comprises the following steps of: firstly, dissolving AES electrostatic defogging liquid generated in the process of processing AES sulfonated exhaust gas by an electrostatic defogger in water; adding a pH regulator into the mixture; uniformly mixing until pH is 7-8; and then compounding the uniformly mixed mixture with a surfactant to obtain an auxiliary agent.