A biological detection method for dioxin compounds in serum and its diagnostic use in predicting metabolic syndrome and related conditions are disclosed. The method of detecting dioxin compounds include obtaining a serum sample by heat-inactivating total serum obtained from a subject, preparing a transformed cell line by introducing a recombinant vector comprising a gene construct in which at least one dioxin-responsive element is operably linked to a promoter and a reporter gene into a host cell, culturing the transformed cell line with the serum sample, detecting the activation of the reporter gene in the transformed cell line, and determining that the dioxin compound is included in the serum sample when the activation of the reporter gene is detected. The serum detected by the method can be used as a surrogate serum biomarker to correlate serum content with disease factors and to predict the occurrence of disease and determine treatability.