Targeted metabolomics is recognized as a quantitative method for the identification and quantitative analysis of targeted metabolic compounds in organisms, which refers to the standard substances of targeted metabolites. The commonly used techniques include conventional liquid chromatography-mass spectrometry (LC-MS) and selective reaction / multiple reaction monitoring (MRM / SRM). Targeted metabolomics provides composition and content information of metabolites, which are closely related to the biological activities and can vary distinctively under different physiological conditions. Therefore, metabolomics methods are important for studying the biological function and comparing the metabolic systems of different organisms. According to the different study materials, there are many targeted metabolism services, such as short chain fatty acid targeted metabolism, bile acid targeted metabolism, fatty acid targeted metabolism, flavonoids targeted metabolism and so on.