An ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method was established for the determination of typical Alternaria toxins in edible vegetable oil. Using an orthogonal array design, the optimal extraction conditions were found to be vortex-assisted extraction with 4 mL of methanol-acetonitrile solution (1:1, V/V) for 10 seconds. Chromatographic separation was conducted on a Waters BEH C₁₈ (100 mm × 2.1 mm, 1.7 μm) column with gradient elution using a mobile phase consisting of acetonitrile and 1 mmol/L ammonium carbonate. Detection was performed using an electrospray ionization source operated in the negative ion mode with multi-reaction monitoring (MRM). Good linearity was observed for tenuazonic acid over the concentration range from 0.02 to 0.2 mg/L, and for alternariol, altenuene, tentoxin and alternariol monomethyl ether over the concentration range from 0.002 to 0.2 mg/L, with correlation coefficients not less than 0.998. At spiked levels from 0.002 to 0.2 mg/kg, the average recoveries of the five toxins in sunflower seed oil and soybean oil ranged from 98% to 118% with relative standard deviations (RSDs) ranging from 2.9% to 17.4%. The limits of quantitation (LOQ) for the analytes were 0.002–0.02 mg/kg. The developed method is suitable for the detection of typical Alternaria toxins in edible vegetable oil.