In this study, a series of different generation hyperbranched poly(amine-ester) with hydroxyl as terminal group were synthesized and used as protectants to synthesize gold nanoparticles with a facile and highly reproducible method. The effect of hyperbranched poly (amine-ester) generation on size and their distribution of gold nanopartciels were discussed. The results of ultraviolet visible absorption spectroscopy, Transmission electron microscopy and scanning electron microscopy showed that the mean diameter were 24.3 +/- 2.6 nm, 18.2 +/- 2.1 nm, and 13.6 +/- 1.5 nm corresponding to the different generation hyperbranched poly(amine-ester), and the synthesized gold nanoparticles were almost monodisperse with a narrow size distribution. (C) 2011 Wiley Periodicals, Inc. J Appl Polym Sci 122:2849-2854, 2011