Abstract: We established a method for simultaneous determination of 12 heterocyclic aromatic amines (HAAs) in fish processing products using ultra-high performance liquid chromatography-electrospray ionization tandem mass spectrometry (UPLC/ESI-MS/MS). After optimizing the conditions, taking ethyl acetate, ammonia and triethylamine as extraction solutions, we purified the extract with MCX SPE column, and eluted by V(methanol) : V(ammonia)=9 : 1. Based on a Thermo Hypersil Gold C18 column, we performed a gradient elution separation by methanol and a gradient elution with the mobile phase of 5 mmol·L^-1 ammonium acetate. Electrospray ionization source was applied and operated in positive ion mode, using selected reaction monitoring (SRM) scan mode and internal standard method for quantitative analysis. The results reveal that 12 HAAs show a good linear relationship within 1.0~100.0 μg·L^-1 (R>0.99). The separation was finished within 12 min. The average recovery (n= 6) of the 12 HAAs spiked in tested samples at 3 levels ranged from 42.98% to 125.00% with the relative standard deviation (RSD) between 1.49% and 9.88%, and the limit of detection (LOD) was in the range of 0.3~1.0 μg·kg^-1. This simple, rapid and highly accurate method can effectively determine various HAAs in fish processing products, easily be applied and popularized.