SnO2/TiO2 nanocomposite photocata- lysts were prepared from TiCl4 and SnCl4·5H2O by supercritical fluid combination technique (SCFCT). This novel SCFCT is a combination of supercritical fluid drying method and sol-gel method. The XRD, TEM and FTIR results show that a new kind of active particle (Ti, Sn)O2 has formed and there is no sign of SnO2 crystals observed in the range of the doping concentration studied. The samples’ photocatalytic activity was evaluated by the degradation of acrylic acid. The results indicate that the SnO2/TiO2 nano- composite photocatalysts prepared through SCFCT show significant improvement in catalytic activity as compared to pure TiO2 or SnO2/TiO2 catalysts pre- pared by traditional drying (TD). The effect of H2O2 (0.167 v%) on the photodegradation was also inves- tigated. After the addition of H2O2, the chemical oxy- gen demand (COD) of acrylic acid, which had been treated with (15.1 mol%) SnO2/TiO2 nanocomposite photocatalysts for 3 h, was reduced from 400―500 to 20 mg/L. SnO2 / TiO2 nanocomposite photocata- lysts were prepared from TiCl4 and SnCl4-5H2O by supercritical fluid combination technique (SCFCT). This novel SCFCT is a combination of supercritical fluid drying method and sol-gel method. The XRD, TEM and FTIR results show that The new photocatalytic activity was evaluated by the degradation of acrylic acid. The results indicate that the SnO2 / TiO2 nano-composite photocatalysts prepared through SCFCT show significant improvement in catalytic activity as compared to pure TiO2 or SnO2 / TiO2 catalysts pre- pared by traditional drying (TD). The effect of H2O2 (0.167 v%) on the photodegradation was After the addition of H2O2, the chemical oxy- gen demand (COD) of acrylic acid, which had been treated with (15.1 mol%) SnO2 / TiO2 nanocomposite photocatalysts for 3 h, was reduced from 400-500 to 20 mg / L.