Preparation methods and catalysis activity of the photocatalyst of nanometer TiO2/conjugated polymer complex were studied in the present research. The target catalyst could be activated by absorbing both ultraviolet and visible light (190-700 nm), whereas pure TiO2 absorbs ultraviolet rays (<380 nm) only. Furthermore, studies showed that the photocatalyst employed in this paper could depigmentize methyl orange solution in a few minutes under visible light. TiO2/conjugated polymer complex was a photocatalyst with high catalytical activity. The temperature of calcination plays an important role in depigmentation. The effect is summarized as-520greater than or equal to560much greater than600>480much greater than440much greater than400 degreesC. The effect contributed to the TiO2 structure form changes and the increase of the degree of polymer conjugation. (C) 2003 Elsevier B.V. All rights reserved.