The invention belongs to the field of biological medicines, and relates to an application of conjugated linoleic acid or derivatives thereof in the aspect of preparing an acetaldehyde dehydrogenase activity accelerant and alcoholic liver injury relieving preparations. The invention provides the novel application of the conjugated linoleic acid or the derivatives thereof (in particular conjugated linoleic acid glyceride); and based upon animal experiments, it proves that the conjugated linoleic acid or the derivatives thereof can improve the activities of liver acetaldehyde dehydrogenase and cytochrome P4502E1 and can relieve the pathological change degree of liver with alcoholic liver injury.