Aldehyde dehydrogenase 2 (ALDH2) is a key enzyme of al-cohol metabolism and it is involved in the cellular mecha-nism of alcohol liver disease. ALDH2 gene mutations exist in about 8％ of the world's population, with the incidence reaching 45％ in East Asia. The mutations will result in im-pairment of enzyme activity and accumulation of acetalde-hyde, facilitating the progression of other liver diseases, in-cluding non-alcoholic fatty liver diseases, viral hepatitis and hepatocellular carcinoma, through adduct formation and inflammatory responses. In this review, we seek to sum-marize recent research progress on the correlation between ALDH2 gene polymorphism and multiple liver diseases, with an attempt to provide clues for better understanding of the disease mechanism and for strategy making.