In view of the characteristics of high hardness, high temperature and high salt in Tazhong 402CⅢ reservoir, the foam agent was selected by means of experiments of compatibility, foamability and thermal stability. The operation parameters were ascertained by physical simulation experiment. Oil displacement experiment was also conducted under the reservoir condition. The results indicate that，under the reservoir condition (temperature 110 ℃, salinity 11.52×104 mg/L, Ca2+&Mg2+ 7 654 mg/L), CS-1 was optimized as foaming agent for foam flooding and the working concentration was 0.2%-0.3%. Gas-liquid mixed injection with gas liquid ratio of 1.5∶1, 1 mL/min of injection rate and 0.5 PV of injection quantity were the best operation parameters of foam flooding. And oil displacement ex? periment shows water flooding recovery increases by 4.12% on the basis of 56.63%. It can provide reference to further enhance oil recovery (EOR) of the high temperature and high salt oil fields.