The invention relates to a method for detecting a plurality of mycotoxins in a sesame paste, and particularly relates to a method which carries out pre-treatment by an optimized dispersive solid-phase extraction method (QuEChERS), and simultaneously detects 26 mycotoxins in sesame paste by ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS / MS). The method particularly comprises: extracting a sample twice with acid-containing acetonitrile-aqueous solutions with different concentrations, adding magnesium sulfate and sodium chloride into the sample extract for salting out, performing centrifugation, adding n-hexane into the obtained supernatant, performing vortex oscillation and degreasing, purifying the product with C18 and magnesium sulfate, performing vacuum concentration, dissolving the residues again with methanol and water in order to obtain a sample analytic solution, and detecting the solution by a multi-reaction monitoring mode of ultra-high performance liquid chromatography-tandem mass spectrometry. The method improves the detection efficiency, saves detection cost, is high in sensitivity, high in repeatability, and high in adding standard recovery rate, and can be extended to detection of other samples with a high grease content.