During the operation of the power plant, the test results of ion chromatography are used to determine the invasion of corrosive and non corrosive ions, identify and exclude the sources and causes of corrosive ion invasion. The invasion of inorganic anions, cations, and organic acid anions (formic acid, acetic acid, etc.) has a significant impact on the safe and economic operation of the unit. The commonly recommended and adopted water and steam quality standards are: when using LPT, according to the provisions of DL/T805.2-2004: boiler drum pressure is 12.7-15.8MPa, chloride content ≤ 2mg/L; The pressure of the boiler steam drum is between 15.9-19.3MPa, and the chloride ion content is ≤ 0.5mg/L.At present, there is no standard for chloride content in steam and feedwater in China. According to the standards of EPRI in the United States, the chloride content in steam and makeup water should be controlled below 3ug/L. For the control of the content of sulfate ions and small molecule organic acids such as formic acid and acetic acid, close monitoring should be carried out to prevent corrosion of the thermal system and to identify the cause in case of abnormal fluctuations in content.