For natural gas well in sour gas reservoirs, very serious corrosion in the completed well system is an important factor of gas production system life. In order to ensure the long-term development of gas wells, this paper mainly introduces material corrosion prevention technology in the completed well system, such as corrosion-resistant alloy steel corrosion control technology, bimetallic combination tubing, corrosion inhibitor technology and so on. By taking LJ Gas Field as an example, this paper introduces the material corrosion prevention technology in the completed well system in LJ Gas Field. For application in the completed well system in LJ Gas Field, the technology above have good performance of corrosion resistance.