Due to lack of common criterion for the photocatalytic activity estimation, it is hard to evaluate the photocatalytic efficiency of the nano-structured titania in different instance. In this paper, we compared the photodegradation efficiency of nano-titania films, by using dichloroacetic acid, rhodamine B and methyl orange as the photocatalytic referents and the ultraviolet lamp as the source light to generate the photocatalytic reaction. The thermal stability and photosensitivity of these referents were determined in order to reach the specific photocatalytic activity of the nano-structured titania in each case. At the same time, we discussed the characters of these referents under the different pH and both with and without oxygen pumping, with the aim of finding the proper one for the photocatalytic efficiency evaluation. （From : No.2, 2006 Glass & Enamel )