Abstract: Aiming at the need of the high temperature and high salinity reservoir to increase active oil, the technical research on the ultra high molecular weight hydrophobic associative polymer has been carried out. The increasing viscosity ability and sewage adaptability is studied through single well injection test, and the infectivity and applicability of the ultra high molecular weight hydrophobic associative polymer has been evaluated. The results show the single well injection test dynamic feedback is good. After the injection test, the injection pressure is increased 4.0 MPa, the flow resistance factor is increased too, the water injection profile is improved, and the corresponding oil well has achieved preliminary effect. The ultra-high molecular weight hydrophobic associative polymer flooding is a new technology of improving oil recovery in high temperature and high salinity reservoir.