A lipophilic silica/metatitantic acid(denoted as Si O2/H2 TiO 3) nanocomposite was synthesized by hydrothermal reaction with surface-modified Si O2 as the lipophilic carrier. As-synthesized Si O2/H2 TiO 3nanocomposite was used as a catalyst to promote the aquathermolysis reaction of extra-heavy crude oil thereby facilitating the recovering from the deep reservoirs at lowered temperature. The catalytic performance of the as-synthesized Si O2/H2 TiO 3catalyst for the aquathermolysis reaction of the heavy oil at a moderate temperature of 150 °C was evaluated in relation to the structural characterizations by TEM,FTIR,XRD and FESEM as well as the determination of the specific surface area by N2adsorption–desorption method. Findings indicate that as-synthesized Si O2/H2 TiO 3nanocomposite exhibits an average size of about 20 nm as well as good lipophilicity and dispersibility in various organic solvents; and it shows good catalytic performance for the aquathermolysis reaction of the extra-heavy oil extracted from Shengli Oilfield of China. Namely,the assynthesized Si O2/H2 TiO 3catalyst is capable of significantly reducing the viscosity of the tested heavy oil from58,000 c P to 16,000 c P(referring to a viscosity reduction rate of 72.41%) at a mass fraction of 0.5%,a reaction temperature of 150 °C and a reaction time of 36 h,showing potential application in downhole upgrading heavy crude oils. A lipophilic silica / metatitantic acid (denoted as Si O2 / H2 TiO 3) nanocomposite was synthesized by hydrothermal reaction with surface-modified Si O2 as the lipophilic carrier. As-synthesized Si O2 / H2 TiO 3 nanocomposite was used as a catalyst to promote the The catalytic performance of the as-synthesized Si02 / H2TiO3catalyst for the aquathermolysis reaction of the heavy oil at a moderate temperature of 150 ° C was evaluated in relation to the structural characterizations by TEM, FTIR, XRD and FESEM as well as the determination of the specific surface area by N2adsorption-desorption method. Findings indicate that as-synthesized Si02 / H2TiO3nanocomposite exhibits an average size of about 20 nm as well as good lipophilicity and dispersibility in various organic solvents; and it shows good catalytic performance for the aquathermolysis reaction of the extr a-heavy oil extracted from Shengli Oilfield of China. Namely, the assynthesized Si O2 / H2TiO3catalyst is capable of significantly reducing the viscosity of the tested heavy oil from 58,000 cP to 16,000 cP (referring to a viscosity reduction rate of 72.41%) at a mass fraction of 0.5%, a reaction temperature of 150 ° C and a reaction time of 36 h, showing potential application in downhole upgrading heavy crude oils.