Abstract: This paper introduces a kind of rapid detection of trichloroethylene pH indicator.The indicator from hydrochloric acid and distilled water,bromocresol green or cresol red composition,and acid and alkali reaction with the indicator discoloration combined.Practice shows that through hydrochloric acid to adjust the color range of the indicator,distilled water extraction,acid and alkali neutralization reaction,organic combination of indicator discoloration,timely monitoring trichloroethylene ph change,suitable for rapid detection of production operation.