• Facet-dependent PS activation by irradiated hematite for efficient degradation of organic pollutants was investigated. • Hematite NPs with {001}-dominated facet exhibited the best catalytic activity in PS activation. • Efficient PS activation by hematite NPs is due to the preferential adsorption of PS and easier Fe(Ⅲ) reduction on the NPs. Hematite has been well studied in advanced oxidant processes (AOPs) due to its abundance and non-toxicity, but its precise mechanism in persulfate (PS) activation remains unclear. Here, we studied PS activation by hematite nanoplates (NPs) with dominant {001} facets, nanocubes (NCs) with dominant {012} facets, and nanorods (NRs) with dominant {110} facets, disclosing the facet-dependent PS activation for efficient degradation of organic pollutants over hematite crystals under visible light irradiation. Hematite NPs exhibited much higher oxidation degradation of organic pollutants than NCs and NRs. Density functional theory (DFT) calculation confirms that PS was more easily adsorbed by NPs than by NCs and NRs, which favored more PS-Fe(Ⅲ) complexes on the surface of hematite NPs. More reduced Fe(II) species from NPs than from others under visible light irradiation promoted PS activation, producing radicals for pollutants oxidation. These findings highlight the structure-performance relationship of irradiated hematite and the mechanisms in contaminant degradation.