The study focuses on the preparation and evaluation of amphiphilic Janus-SiO₂ nanoparticles for enhanced oil recovery in low-permeability, dense, and high-salt reservoirs. The nanoparticles, modified with trichloro(octyl)silane and aminopropyl triethoxysilane, exhibit uniform size distribution (30-50 nm) and good dispersion in mineralized water. They show excellent interfacial activity, with interfacial tension between 10⁻² mN/m, and can enhance rock wettability. Under conditions of 65 °C and 8000 mg/L salinity, 0.5 PV of 0.05% amphiphilic nanoparticle dispersion increased oil recovery by 14.6% compared to water flooding. The mechanism involves reducing oil-water interfacial tension, changing rock wettability, and increasing shear viscosity at the oil-water interface. These properties make amphiphilic Janus-SiO₂ nanoparticles promising for enhancing oil recovery in high-salt and low-permeability reservoirs.The study focuses on the preparation and evaluation of amphiphilic Janus-SiO₂ nanoparticles for enhanced oil recovery in low-permeability, dense, and high-salt reservoirs. The nanoparticles, modified with trichloro(octyl)silane and aminopropyl triethoxysilane, exhibit uniform size distribution (30-50 nm) and good dispersion in mineralized water. They show excellent interfacial activity, with interfacial tension between 10⁻² mN/m, and can enhance rock wettability. Under conditions of 65 °C and 8000 mg/L salinity, 0.5 PV of 0.05% amphiphilic nanoparticle dispersion increased oil recovery by 14.6% compared to water flooding. The mechanism involves reducing oil-water interfacial tension, changing rock wettability, and increasing shear viscosity at the oil-water interface. These properties make amphiphilic Janus-SiO₂ nanoparticles promising for enhancing oil recovery in high-salt and low-permeability reservoirs.