Metabolomics is a discipline that uses Chromatography-Mass Spectrometry and Nuclear Magnetic Resonance techniques to identify and quantify all small molecule metabolites in living organisms and biological samples, which relies on sensitive, stable analytical procedures and improving databases. Metabolomics has been widely used in medicine, food science, crop and farm animal research, and other fields. Metabolomics can establish a more direct relationship between changes in the type and content of metabolites and phenotypes. Metabolomics has gradually become a new research method for the analysis of genetic mechanisms of complex traits following genomics, transcriptomics, and proteomics with the advances in omics technology. In this review, we firstly introduce common analytical strategies, metabolomics platforms, and metabolomics databases. Then, we review the application of metabolomics in metabolic molecular identification of important economic traits in agricultural animals, disease diagnosis, meat quality and safety detection of animal products. We also introduce the latest achievements in the development, formation and analysis of important traits of animals and plants by using metabolomics, transcriptome, and genomics. Overall, the integrated analysis of metabolomics and other omics can comprehensively explain the genetic mechanism of all kinds of complex traits and help to improve the complete biological process of "mutation-gene-expression-metabolism-phenotype". Metabolomics provides a new method for the mechanism analysis of complex characters and a novel idea for new agricultural breeding.