Photocatalysis provides a clean way to decompose harmful VOC, Volatile Organic Compounds. However, the light wavelength is another important factor to determine the effectiveness of photocatalysis process besides the type of photocatalyst. This experiment reveals that the VUV light stimulates TiO2 photocatalyst to perform an effective decomposition of toluene which is not able to be decomposed by UVC, UVB or UVA photocatalysis.