The improving oil recovery experiment of fracture dense high salinity reservoir was carried by air foam flooding. The ability of foam foaming agent，the half-life and salt resistance，and the effects of gas-liquid ratio on foam stability were evaluated by use of self-developed high-temperature and high-pressure device. The matrix core injectivity of air foam flooding，oil displacement efficiency and the ability of improving seepage cracks were researched through physical simulation device. The results showed that the foam volume of SFR-173 anionic-nonionic foaming agent in deionized water and simulated formation water was 290 and 340 mL，the half-life of that was 368 and 330 min，and the foam composite index was 6370 and 6697，respectively，indicating best foam performance. When the salinity increased from 7 to 56 g/L，the foam volume of 0.5% SFR-173 decreased from 370 to 340 mL，producing liquid time decreased from 174 to 122 s and the half-life reduced from 778 to 330 min. Under the formation condition，the foam volume increased and became gradually stable with increasing gas-liquid ratio. The optimum gas-liquid ratio was between 1∶1 and 2∶1. Air foam injection results in dense oil reservoir showed that with the increase of injection volume，the core pressure at both ends and the drag coefficient increased and became gradually stable，and the maximum value was 31.4 MPa and 1.74，respectively. The oil displacement efficiency increased by 17.86% after water flooding transferred to air foam flooding. Under the condition of crack heterogeneous reservoir，the water flood oil recovery was only 39.14% when the moisture content was 98%. The air foam flooding could effectively improve the utilization of core matrix condition and seal cracks seepage channel. The oil recovery of matrix core increased from 12.59% and 21.21% to 49.87% and 72.0%.