Aiming at the problems of gas channeling and low sweep efficiency of CO₂ flooding in micro-fractured reservoirs，the effects of anionic，zwitterionic and non-ionic CO₂ foaming agents and water-soluble and gas-soluble nanoparticle foam stabilizers on foam performance were evaluated by laboratory experiments. The nano-composite supercritical CO₂ foam system was optimized as 0.3% foaming agent CAB-35 + 0.5% water-soluble nanoparticle foam stabilizer As30 GA，and the foam performance of the nano-composite supercritical CO₂ foam system under reservoir conditions was studied. At the same time，the core flooding experiment of the nano-composite supercritical CO₂ foam system was carried out in the reservoir environment. The results showed that the foaming volume of the nano-composite supercritical CO₂ foam system was 550 mL，the half-life was 47 min，indicating good foaming and foam stability performance. The viscoelastic modulus of nano-composite supercritical CO₂ foam system was about 90 mN/m higher than that of ordinary foam（0.3% CAB-35）. The foam strength and stability were greatly improved by the synergistic effect of foaming agent and nano-particles. The nano-composite supercritical CO₂ foam system had good temperature resistance and pressure resistance. Under the reservoir conditions（salinity of 10×10¹ mg/L，80 ℃，42 MPa），the foaming volume reached up to 275 mL，and the half-life was 72 min. The plugging and oil displacement performance of nanocomposite supercritical CO₂ foam system in porous media was studied by physical model. In the gas-liquid ratio of 0.5—2.0，the maximum plugging pressure difference of core displacement was 1.6 MPa，the resistance factor was greater than 50，and the recovery degree was 28.8 percentage points higher than that of ordinary foam. The nano-composite supercritical CO₂ foam system had good stability，high sweep efficiency，excellent ability to improve oil recovery，and broad application prospects.