Abstract: As a kind of multifunction enzyme system, CYP450 enzyme have extensive biological significances. It is related to biological transformation of xenobiotics and metabolism of endogenous substances, and also participates in the metabolic inactivation of drug toxicity as a major enzyme system of drug metabolism in hepatocyte. As the diversity of structure, function and gene regulation in P450 enzymes the research on it has been a hot spot in toxicology study since it was found. In this article, it is summarized the subtypes of CYP450 related to drug metabolism and the interactions with drugs, and discuss the interaction mechanism between P450 enzymes and the xenobiotics.