Polycyclic aromatic hydrocarbons (PAHs) are a large group of persistent organic pollutants that widely exist in the environment. The risk of PAHs exposure has increased with the increasing industrialization and fossil fuels consumption in China. It has been reported that PAHs are potential risk factors for asthma in children, but the specific pathogenesis has not been fully clarified. In recent years, the development of metabolomics has provided a promising approach to elucidate the toxicological mechanism of environmental pollutants. In this paper, we will review the mechanism of PAHs mediating inflammation and inducing childhood asthma by changing epigenetic patterns and activating aromatic hydrocarbon receptor signaling pathway from the perspective of metabolism, especially one carbon metabolism and tryptophan metabolism.