Abstract: In running the φ177.8 mm liner string in well Moxi009-4-x2, many difficulties have been expected to be encountered, such as high bottom hole temperature, long cementing section, long and active oil and gas shows, drilling fluid of high density that are severely contaminated, and decreased mud density in the next interval, etc. To deal with these difficulties, a high strength high density anti-gas-migration cement slurry and a high performance contamination-resistant spacer fluid have been developed based on the choice of weighting materials and studies on these issues such as the mechanisms of enhancing the toughness of set cement through expansion, the mechanism of cement slurry contamination, and the optimization of cementing techniques. With the cement slurry, the spacer, and the corresponding techniques, the development of the strength of the top cement slurry has been accelerated, and the toughness of the high density set cement has been improved. The contamination of cement slurry and drilling fluid has been minimized, and the bond strengths of set cement with casing string and borehole wall have been enhanced. 94.5% of the liner string cemented has been up to the standard, and the merit factor of cementing job has reached 74.8%. This cementing technology provides a support for the improvement of the quality of well cementing in the area, and a guarantee for the safe and efficient development of the deep high pressure wells in Anyue gas field.