Abstract: Nanoflake structured titanium dioxide was successfully prepared from electric furnace molten slag by using a hydrothermal method under the condition of alkaline solution. The effects of hydrothermal temperature, reaction time and sodium hydroxide solution concentration on the titanium extraction and morphology were investigated. Relatively pure and better crystallized nanoflake structured titanium dioxide can be obtained with increasing reaction temperature, time and alkaline solution concentration. The optimum preparing conditions are that the hydrothermal temperature is above 180℃, the reaction time is above 24 h and the concentration of NaOH solution is 12 mol·L^-1. Using the as-prepared TiO₂ as a photocatalyst, the degradation rate of methyl blue is above 81.1% under a xenon lamp for 90 min.