A series of experiments were conducted according the formation condition of Bohai Oilfield, and applicability conditions and optimum parameters were gained. From economic considerations, foam injection volume should be from 0.3 to 0.5 PV. Applicable permeability ratio range of foam flooding is less than 15. When permeability variation coefficient is from 0.64 to 0.72, oil recovery improvement is the highest. When water cut of produced fluid for water flooding is from 80 % to 90 %, the effect of foam injection is the best. The blocking effect of foam in core is good for gas liquid ratio from 0.5 to 2.5. Considering gas crossflow, gas water ratio should be limited from 0.5 to 1.0. Slug injection is better than continuous and SAG injection methods. If there is high-permeable layer or high capacity channel with permeability higher than 10 D, deep blankoff using blocking agent should be implemented before foam injection.