The present invention pertains to the field of optical functional materials, and in particular relates to a fluorescent dye having a structure as shown in Formula (I). The fluorescent dye having the structure is covalently bonded to a biological macromolecule, and is stable. The fluorescent dye has high sensitivity, and can be used for different applications, such as cell imaging, fluorescent probes, laser dyes, and fluorescence sensors, and exhibits excellent utility. The preparation method provided by the present invention has low raw material costs, high yields, and employs a simple process that does not produce pollution. The prepared fluorescent dye has a novel structure and excellent properties, and is suitable for a wide range of applications in the fields of biology and environmental science.