The instrument air compressor air used in chemical production of Shouyang Chemical Corporation Ltd. of Yangmei Group can be used as the factory air and instrument air in maintenance link. In order to ensure efficient maintenance link, its circulating water system needs to be reformed. By adding a set of glass fiber reinforced plastic cooling tower system, the circulating water system of the instrument air compressor was reformed and the process was optimized, the purpose of the company's water system shutdown and maintancement without interrupting the instrument air has been realized.