This standard specifies a specific method for the determination of trace moisture in gases using the electrolysis method, which is applicable to gases such as nitrogen, hydrogen, neon, argon, carbon dioxide, etc. The measurement range is 0.1 × 10 ^ -6 to 1,000 × 10 ^ -6 (volume fraction). The standard describes in detail the principle of the method, including the process of applying a DC voltage between electrodes in Electrochemical cells to cause moisture to be electrolysis into hydrogen and oxygen, and deduces the relationship between moisture content and electrolysis current according to Faraday's law of electrolysis and gas law. The standard also covers instrument requirements, calibrating, measurement matters, precision, result processing and test reports to ensure the accuracy of the determination.