To solve steam overriding and steam channeling in steam flooding, sulfonate surfactant ZAS, polyether sulfonate surfactant ZCP-1 and nanoparticle NS were compound to found a three-phase foam system with temperature resistance of 300 ℃ which formula was 0.5% ZAS/ZCP-1（mixed proportion was 3∶1）+1.0% NS. Then evaluated its foam performance, temperature resistance, plugging performance and oil displacement performance was evaluated through experiments. The results showed that the three-phase foam system had excellent foam performance at room temperature, the foam volume was 680 mL, the liquid half-life was 26.67 min, and the foam half-life was 12 h, and it was stable after heat aging at the temperature of 300 ℃. The three-phase foam system could stably exist at a high temperature condition of 300 °C and had blocking ability to selectively seal high permeability layers. Its resistance factor was greater than 30 within the permeability range of 1000×10^-3—4000×10^-3 μm² , meantime, its blocking ability increased with the increase in permeability. Under the heterogeneous condition with a permeability difference of 1∶2, it could improve the total oil recovery by 17.93%, as a result of adjusting the steam absorption profile and increasing the oil recovery of the low-permeability model. The three-phase foam system has good potential to improve the oil recovery of steam flooding.