In order to conveniently monitor the concentration of poly(aspartic acid) (PASP) used as a green scale inhibitor in cooling water systems, and to improve calcium phosphate inhibition, carbazole and hydroxy groups-tagged PASP (CHGTPASP) was synthesized by ring-opening reaction of N-(2,3-epoxylpropyl)carbazole (EPC) with partially ethanolamine-modified polysuccinimide (PEAMPSI) followed by alkaline hydrolysis. CHGTPASP has good Ca(3)(PO(4))(2) and CaCO(3) inhibition and its fluorescence intensity (Fi) is good linear to concentration. These multifunctional properties are of importance in industrial water processing economically and environmentally.