In this work, representative semiconductors CdS, V2O5, WO3 and P25 (Degussa TiO2 consisting of 80 wt% anatase and 20 wt% rutile) were chosen as the photocatalysts, and the common phenol along with its derivatives (p-nitrophenol, p-chlorophenol and hydroquinone) were designated as the probe pollutants. The energy levels of the frontier molecular orbitals (E-HOMO and E-LUMO) of organics, and the valence band (VB) and conduction band (CB) energy levels (E-VB and E-CB ) of photocatalysts were obtained through experiments and calculations. By correlating the photocatalytic activities of photocatalysts for the degradations of the organic pollutants under the irradiation of a 300 W xenon lamp with their above-mentioned energy levels, some new findings can be acquired. To be specific, the more positive E-HOMO of an organic pollutant leads to its easier photodegradation by photocatalysts. Meanwhile, the more negative VB position for a photocatalyst results in the higher photocatalytic activities for the degradations of organic pollutants. Therefore, the matching correlation between the E-HOMO of an organic pollutant and the E-VB of a photocatalyst is of great importance to the efficiency of photocatalytic degradation. (C) 2018 Elsevier Inc. All rights reserved.