The invention relates to 2-(thiazol-2-yl)imino-5-(benzylidene)thiazolidin-4-one shown as formulas I, II, III or IV or a mixture thereof, wherein R1 is selected from hydrogen, C1-C2 alkyl or C3-C4 straight-chain or branched chain alkyl, R2 is selected from hydrogen, C1-C2 alkyl or C3-C4 straight-chain or branched chain alkyl, X1-X5 are selected from hydrogen, C1-C2 alkyl, C3-C4 straight-chain or branched chain alkyl, nitro, amino or NHCOR, and R is selected from hydrogen, C1-C2 alkyl or C3-C4 straight-chain or branched chain alkyl. Applications of the 2-(thiazol-2-yl)imino-5-benzal thiazoline-4-one or the mixture thereof in preparation of neuraminidase inhibitors are also disclosed.