In this study, firstly the degradation of different chlorophenols (CPs) in a novel ultrasound-irradiated Fenton-like system was investigated. Then, based on the selected quantum chemical and physicochemical descriptors, by the use of partial least squares analysis, a good prediction quantitative structure-property relationship for the obtained degradation rate constants of CPs in the anaerobic culture was obtained. It was found that the energy of the highest occupied molecular orbital, characterizing the ability of a molecule to lose electrons or to be oxidized, played an important role in the CPs disappearance process. The greater the Dipole moment value, the higher the CPs degradation rate constant. And CPs with large absolute hardness values tended to have slow degradation rate. The model can be also used to explain the degradation mechanism and enhancement role of ultrasound. It can be concluded that the degradation of CPs in the US/Fenton- like system can be ascribed to homogeneous Fenton oxidation in the bulk solution. The synergistic role of US irradiation is expected to enhance Fenton reaction instead of directly decompose CPs in the system. (C) 2009 Elsevier B.V. All rights reserved.