The preparation of nano oil displacement materials with high interfacial activity remains a critical issue for the application of nanotechnology in ultra-low-permeability reservoirs to enhance oil recovery. The surface interfacial activity of self-made amphiphilic carbon dots（CDs）and high interfacial activity was investigated. The effects of inorganic salts and aging temperature on the interfacial activity of the CDs were studied，and the oil film removal and wettability alteration properties of the CDs were determined. Finally，the oil displacement efficiency of the CDs was evaluated by the core flooding experiments. The results showed that amphiphilic CDs had similar surface tension curves to surfactants，and the surface tension at critical micelle concentration and surface tension was 150.21 mg/L and 28.43 mN/m，respectively. Furthermore，amphiphilic CDs could maintain high interfacial activity at cNaCl =100 g/L and cCaCl₂ =25 g/L，reducing interfacial tension from 0.578 mN/m to 0.032 mN/m and 0.015 mN/m. In addition，amphiphilic CDs had excellent oil film removal efficiency and wettability alteration performance，which could effectively remove residual oil in the form of oil film from the sandstone surface and reduce the contact angle of water droplets in the air from 109.2° to 44.8°. Finally，core flooding experiments showed that the oil displacement efficiency of amphiphilic CDs was 17.4% in the presence of 85 g/L NaCl and 10 g/L CaCl₂. Therefore，as temperature-resistant and salt-tolerant nanoparticles with ultra-small size，amphiphilic CDs have broad application prospects in enhancing oil recovery in high-temperature and high-salt reservoirs.