Objective:To compare structure and function of mite Der f 3,Der p 3 and Eur m 3.Methods: Obtained mite allergens amino acid sequences from the International Union of Immunological Societies nomenclature database .Then physiochemical characterization,sequence alignment,secondary structure,three dimensional (3D) structure and epitopes of three proteins were analyzed by bioinformatics methods.Results:According to results of alignment ,Der f 3,Der p 3 and Eur m 3 displayed 88.51%sequence iden-tity.Der f 3,Der p 3 and Eur m 3 all contained three active sites and two trypsin functional domains ,which showed high identity of amino acid residues.Active sites of three proteins ,which closing to each other in three dimensional (3D) structure,constituting the active center of the enzyme.Secondary and 3D structure of three proteins all contains α-helices,β-sheets and random coils.Epitopes analysis revealed that Der f 3,Der p 3 and Eur m 3 all have 5 main potential epitopes located in random coils.Epitope sequences of Der f 3,Der p 3 and Eur m 3 overlapping in three domains (peptides of 79-81aa,129-135aa and 172-174aa),but the residues in these three domains were not identical.Conclusion:These studies lay the foundation for biochemical and genetic analysis of these 3 allergens,and may contribute to vaccine development for allergen-specific immunotherapy.