Photo-luminescent polymers as a kind of talent functional polymer, have been applied in various field such as bioanalysis, detection and materials. Herein we report a novel fluorescent hyperbranched aliphatic polyestertriazole via one-pot azidation and azide-alkynyl cycloaddition of propargyl (2,2-bismethylsulfinyloxymethyl)propionate, an AB(2) pre-monomer, by heat promotion at 110 degrees C. Under such reaction condition, the methylsulfinyloxy groups were converted into azido groups by NaN3, then azide-alkynyl cycloaddition simultaneously happened to give hyperbranched polyestertriazole (hb-PETA). By the analysis of reaction kinetics monitored with proton nuclear magnetic resonance spectroscopy, the results clarifies that the whole synthesis was achieved efficiently. The obtained hb-PETA exhibited the blue fluorescence in both bulk and solution upon the exposure of UV light although it had no conventional fluorescent group. The emission wavelength and intensity of hb-PETA in solution were dependent on the solvent and the addition of metal ions. Among various metal ions, hb-PETA was particularly sensitive to Hg2+, Cu2+ and Fe3+ in water, and showed the excellent quenching efficiency for Hg2+. Moreover, the Hg2+ detecting in water could be achieved highly rapidly and sensitively. We believe this kind of functional polymer could be used in other biological and material area.