To detect allergens of Litopenaeus vannamei and find peptides for representation of allergens, high-performance liquid chromatography coupled to quadrupole time of flight mass spectrometry (HPLC-QTOF) with database search was used to separate and detect all sequencing grade modified trypsin-digested peptides. And multiple reaction monitoring (MRM) method on triple quadrupole mass spectrometer was established for rapid detection of the peptides of allergens. The results showed that there were seven kinds of allergens in Litopenaeus vannamei, which were Lit v 1 tropomyosin, arginine kinase, Lit v 3 allergen myosin light chain, hemocyanin subunit L1, hemocyanin subunit L2, hemocyanin subunit L3 and troponin C1, and the numbers of identified peptides of allergens were 214, 16, 84, 145, 225, 163 and 93 respectively. The MRM result showed that the established method was of high sensitivity and good selectivity. This paper would providea reference for the analysis of allergens of Litopenaeus vannamei.