Nitrogen doping in combination with the brookite phase or a mixture of TiO 2 polymorphs nanomaterials can enhance photocatalytic activity under visible light. Generally, nitrogendopedanatase/brookite mixed phases TiO 2 nanoparticles obtained by hydrothermal or solvothermal method need to be at high temperature and with long time heating treatment. Furthermore, the surface areas of them are low (<125 m 2 /g). There is hardly a report on the simple and direct preparation of N-doped anatase/brookite mixed phase TiO 2 nanostructures using sol-gel method at low heating temperature. In this paper, the nitrogen-doped anatase/brookite biphasic nanoparticles with large surface area (240 m 2 /g) were successfully prepared using sol-gel method at low temperature (165 • C), and with short heating time (4 h) under autogenous pressure. The obtained sample without subsequent annealing at elevated temperatures showed enhanced photocatalytic efficiency for the degradation of methyl orange (MO) with 4.2-, 9.6-, and 7.5-fold visible light activities compared to P25 and the amorphous samples heated in muffle furnace with air or in tube furnace with a flow of nitrogen at 165 • C, respectively. This result was attributed to the synergistic effects of nitrogen doping, mixed crystalline phases, and high surface area.