Modified graphene oxide nanosheets（MGONS）is a newly developed nanomaterial based on graphene oxides for EOR applications. The size and morphology of the modified graphene oxide nanosheet was examined，the oil/water interfacial tension， emulsifying properties，viscosity，rheological properties of the MGONS/polymer system was performed and the core flooding test was carried out. The results showed that the MGONS had a typical size of 217.7 nm and piled up loosely in the aqueous solution. No matter the MGONS solution or MGONS/polymer mixed system，with a very low concentration of 10 mg/L of MGONS，they could reduce the interfacial tension to 10^-3 mN/m，while the concentration of MGONS was of 50 mg/L，the interfacial tension was 10^-4 mN/m， exhibiting higher activity and the ability to uniformly distribute at the oil/water interface. The water-oil separation time prolonged with the increase of the concentration of MGONS，whether there was polymer or not，indicating that MGONS had a certain emulsifying ability. The MGONS interacted with polymer through hydrogen bond and static interaction. After adding 100 mg/L of MGONS，the viscosity of polymer solution could be increased by 60%. The core flooding test result revealed that the MGONS/ polymer mixture system could enhance oil recovery efficiency by 26.25% based on water flooding.