The invention relates to a near-infrared fluorescent dye and use thereof, and particularly relates to compounds represented by following Formulae A, B and C, wherein each group in the Formulae is described in the specification. Further provided are a dye composition comprising the compound represented by Formula A or Formula B, and a preparation method of the compound represented by Formula A or Formula B. The compound has a maximum absorption wavelength of 880 nm, considerably exceeding maximum absorption wavelengths of the majority of small-molecule near-infrared fluorescent dyes in the prior art. Moreover, the structure thereof does not aggregate even if the concentration thereof is excessively high, thereby having considerably high chemical stability and light stability.