Polycyclic aromatic hydrocarbons (PAHs) are hydrophobic aromatic compounds consisting of two or more condensed benzene rings, having greater teratogenicity, carcinogenicity, mutagenicity and toxicity. The most representative PAHs is benzo(a)pyrene (B[a]p), which is composed of five benzene rings, and is classified as a Group I carcinogen. The treatment technologies for B[a]p removal include bioremediation, physical remediation and chemical remediation. The advanced oxidation technology based on sulfate radicals becomes a recent research hotspot because of its high redox potential, high reactivity and environmental friendliness. Nevertheless, persulfate needs to be activated through various approaches to produce a series of reactive species, and iron-based materials are widely used due to the abundant reserves, environmental friendliness and excellent activation performance. In this paper, pyrite (FeS2) was used as a cheap and non-toxic sulfide mineral, allowing for a slow release of Fe2+ as well as the cycling of Fe2+ and Fe3+. Kaolinite was chosen as a suitable carrier to solve the agglomeration of FeS2 nanoparticles. A composite with FeS2 and kaolinite was prepared to obtain efficient persulfate activation and B[a]p degradation.