A method for simultaneous detection of 28 mycotoxins in edible oil was established by ultra performance liquid chromatography-tandem mass spectrometry. Sample preparation was fulfilled through two-step liquid-liquid extraction and solid-phase extraction sequentially. The methodological verification results showed that the limits of quantification （S/N， 10） ranged from 0.07 μg/kg to 1.25 μg/kg， which were far less than the maximum levels of mycotoxins in foods. In addition， the recoveries of the three-level spiked samples were between 60% and 120%， and the relative standard deviations were less than 12.5%， which could meet the quality control specifications required in the national standard GB/T 27404-2008 Criterion on quality control of laboratories - Chemical testing of food. Using this method， risk monitoring of mycotoxins in the edible oils was executed， showing that aflatoxins， zearalenones and derivatives， sterigmatocysin and T-2 could possibly contaminated edible oils. In peanut oils， aflatoxins， zearalenone and sterigmatocysin were the main mycotoxins while zearalenone and its derivatives were the main mycotoxins in both rapeseed oils and corn oils.