A waterborne aminofluorescein polyurethane-based dye (AF-WPU) with green fluorescence excited by visible light was synthesized by anchoring aminofluorescein (AF) to waterborne polyurethane chains. The structural characteristics of AF-WPU was confirmed by means of 1 H-NMR, FT-IR and UV-vis absorption. Compared with AF, there is a hypsochromic shift, and a new absorption peak generating in the UV-vis spectra of AF-WPU. Meanwhile, AF-WPU emited excellent fluorescence.The fluorescence intensity of AF-WPU increased five times at the same concentration. It is found that the fluorescence intensities of AF-WPU decreaseed with increased temperature, and increased first and then decreased with increasing concentration. The fluorescence of AF-WPU is very stable and insensitive to quenching agents. Moreover, AF-WPU which excited by visible light is less phototoxic to health, and has a broad prospect in practical applications.