Abstract: A certain amount of quality defective liquor will inevitably form during the brewing process of liquor. The existence of defective liquor restricts the production and quality of premium liquor,avoid the production of defective liquor has become a major problem. This paper reviewes the research progress on the chemical essence,detection methods,metabolic microorganisms,biological control and flavor optimization methods of the typical defective maotai-flavor liquor,taking the hetero-smelling substances as the main line,so as to provide reference for the further research on maotai-flavor defective liquor in the future.