Titanium dioxide powder was synthesized by the hydrothermal route with the starting precursors as titanium isopropoxide, ammonium hydroxide and nitric acid. The final of pH value of mixed solution was 1 and treated in the hydrothermal PTFE vessel at 80-100 °C for 3h. The phase of titanium dioxide was characterized by X-ray diffractometer (XRD). The morphology of titanium dioxide was investigated by scanning electron microscope (SEM). The chemical composition of titanium dioxide was examined by energy dispersive X-ray spectrophotometer (EDXS). The photocatalytic degradation of geosmin by titanium dioxide was determined by gas chromatograph coupled with flame ionization detector (GC-FID).