With the characteristic of dissclution of copper salts,the contert of S2-is indi-rectly figared out precipitating the S2-dding excess cpper salt and determining the left Cu2+ by theexlectrogravimetric analysis.This methed is accurate to be employed to measure directly the S2-con-tent in a complex system of mucti-valence sulfides,expecially whin the S2-content is high.