Abstract: Cytochrome P450(CYP450) is a family of metabolic enzymes,and their expression and activity can be regulated by xenobiotics,which lead to a major concern of environmental toxicology.This review systematically summarized the roles and molecular mechanisms of nuclear receptors/transcription factors and microRNA in xenobiotic-regulated expression and activity of CYP450 enzymes,and analyzed the types of regulation and their intermediate factors.Furthermore,it was concluded that there existed an interaction between xenobiotics and CYP450 enzymes through regulation and metabolism,which played an important role in the toxic effects of xenobiotics.This review may help to provide clues for toxicity evaluation,mechanism exploration,and risk assessment of environmental pollutants.