To address the challenges of low water flooding efficiency and limited enhanced oil recovery (EOR) from conventional chemical flooding in conventional heavy oil reservoirs of Xinjiang Oilfield, this study investigated a novel nano viscosity reducer for chemical flooding applications. Nano-SiO? was modified with vinyltrimethoxysilane to prepare an intermediate SiO₂@D containing carbon-carbon double bonds, followed by graft copolymerization with α-olefin sulfonate (AOS) to synthesize an amphiphilic nano-viscosity reducer (SiO₂@AOS). Successful synthesis was confirmed by FT-IR, TG, and SEM characterizations. The results revealed that SiO₂@AOS forms spherical nanoparticles with an average diameter of 15.6 nm. The SiO₂@AOS nanofluid (3 g/L) reduced oil water interfacial tension from 31 mN/m to 4.4 mN/m (an 85.8% reduction) and adjusted the contact angle from 107.2° to 54.3°, significantly altering reservoir wettability. The SiO₂@AOS nanofluid (3g/L) achieved an 89.5% viscosity reduction rate for the conventional heavy oil (62 °C, 1300 mPa.s) and demonstrated 90.2% water separation efficiency in the emulsion system. The SiO₂@AOS nanofluid (3 g/L) flooding and subsequent water flooding can further enhance oil recovery rate by 22.5% based on primary water flooding. This work provided a novel nanomaterial with dual functionalities of high efficiency viscosity reduction and synergistic oil displacement for conventional heavy oil production, showing significant application potential.