Lactococcus spp. are gram-positive facultative anaerobic bacteria that can utilize carbohydrates to produce compounds such as lactic acid and diacetyl， which can impart characteristic flavors to foods. They are widely used in food processing， where they play important roles in improving the quality of dairy products， delaying spoilage， and reducing levels of harmful compounds. Recently， Lactococcus spp. have also gained attention as expression hosts in synthetic biology. Additionally， this bacteria exhibit potential probiotic properties， playing important roles in regulating gut microbiota， modulating blood pressure， inhibiting the growth of harmful microorganisms， and suppressing intestinal inflammatory responses. However， compared to other lactic acid bacteria， research on the understanding of Lactococcus， as well as detection methods and safety assessment remain limited. Therefore， systematically elucidating the functional characteristics and mechanisms of action of Lactococcus， and establishing specific， effective， and accurate detection methods for Lactococcus are crucial for promoting its application in food and safeguarding consumer health. This article reviews the biological characteristics， classification， health functions， food applications， and existing detection methods of Lactococcus spp.， providing a reference for the development and rational regulation of industries related to Lactococcus.