We report herein on a new method to achieve a high yield of hydrocarbons from hydrothermal catalytic hydrodenitrogenation (HDN) of indole, which is higher than that from conventional pyrolysis methods. The main hydrocarbon products were aromatic hydrocarbons and alkanes, which are similar to fossil oils to be used as liquid fuels in the future. Catalyst screening experiments show that noble metal catalysts (e.g., 5 wt % Pt, Pd, or Ru) supported on porous solids (e.g., carbon, Al2O3) enhanced the conversion of indole to hydrocarbons under hydrothermal condition. Of those different catalysts, Pd/γ-Al2O3 shows the greatest influence on the yield of hydrocarbons, which we focus on the catalyst Pd/γ-Al2O3 in more details. On the basis of the Pd/γ-Al2O3 catalyst, the effects of time, temperature, and H2 pressure on the hydrocarbons were discussed. HDN of the indole reaction at 450 °C, 0.015 g/cm3 water density, 5 MPa H2, and 50 wt % Pd/γ-Al2O3 loading led to a maximum yield (51 mol %) of hydrocarbons at 120 min...