Abstract: Structure and performance of a H₂S gas-sensing electrode and its initial application in printing and dyeing sewage analyses are reported in this paper.The H₂S gas-sensing electrode consists of an all-solid state Ag₂S membrane indicating electrode and an all-solid state LaF₃ reference electrode. The practical linear range of the H₂S electrode is within 5×10^-8-1×10^-2M sulfide solution. The electrode responds to hydrogen sulfide is fast and the reproducibility of measurements is better, Except for higher concentration cyanide, iodide and thiocyanide ion other common anions don't interfere with measurements. If the H₂S gas-sensing electrode is used to determine sulfide ion in printing and dyeing sewage (by the addition dilution method), the sample solution does not need any treatment and the electrode will not be contaminated either, because the sensor is hung in air gap over the sample solution. This method is simple, fast, and can be content with requirements of control analyses.