Coenzyme Q (CoQ),also known as ubiquinone,is a lipid-soluble quinone compound which exists in biological organis ms widely.The numbers of side chain isoprene of different sources of coenzyme Q are different.Coenzyme Q in humans and mammals are called coenzyme Q10 (CoQ10 ,Q10 ), in that the ubiquinone side chain of humans and mammals are mainly composed of 10 isoprene units.In the mitochondrial respiratory chain,it acts as a mobile electron transporter and is a cofactor of uncoup-ling proteins,which is an essential endogenous substance in the process of cell respiration and metabo-lis m.Moreover,CoQ possesses independent antiapoptosis feature,which regulates the mitochondrial permeability transition pore.Mitochondrion is an important organelle,which is the place for energy stor-age and supply,providing the energy for vital movement.There are various kinds of chemical toxicants in the hu man environ ment,and they can enter into the hu man body through drinking,feeding or breath-ing and then affect cell mitochondria to different degrees.Thus,it is important for preventive medicine to investigate intervention or reduction of the biological da mage of exogenous chemicals′effects on mito-chondria.In this paper,we reviewed the research progress of the role of coenzyme Q in xenobiotics in-duced mitochondrial da mage.