The photocatalytic performance of sodium pentachlorophenate (PCP-Na) over NaBiO3 under visible light irradiation was first investigated systematically. After I h of photocatalytic reaction, the degradation rate of PCP-Na could reach to 90.5% in appropriate conditions. (OH)-O-center dot is the dominant photooxidant rather than O-2(-) based on the experiment results and density of states (DOS) analysis. The PCP-Na solution became basic (pH value increased to similar to 9) with the progress of photocatalytic reaction which may be attributed to the PCP- oxidized to the pentachlorophenoxy radical by an attack on PCP- by (OH)-O-center dot. The photocatalyic reaction over NaBiO3 follows the rule of first-order reaction according to the Langmuir-Hinshelwood model. The initial concentration of the PCP-Na, the initial pH value of PCP-Na aqueous solution and the amount of NaBiO3 used have great influences on the photocatalytic performance. Three kinds of photocatalytic systems (P25, Bi2O3 and P25-Bi2O3 heterojunction) exhibited relative lower photocatalytic activity compared to NaBiO3 powder. Crown Copyright (C) 2008 Published by Elsevier B.V. All rights reserved.