Abstract: An amino-terminated hyperbranched polyamide copolymer was successfully prepared by the Michael addition and amidation using diethylenetriamine and methyl acrylate as comonomers, and its chemical structure was characterized by FTIR. The resultant copolymer was used for the scale inhibition of industrial circulating water, and the effects of the copolymer dosage, pH value of water environment and water temperature on calcium sulfate inhibition were investigated. The results indicated that the amino-terminated hyperbranched polyamide not only had a good dispersibility for Fe2O3 but also exhibited good scale inhibition for CaSO4, and it achieved a scale inhibition efficiency of 96.37 % at the dosage of 12 mg/L. Moreover, the amino-terminated hyperbranched polyamide also showed an excellent inhibition efficiency under a wide temperature range. The XRD and SEM analyses demonstrated that the amino?terminated hyperbranched polyamide not only could effectively inhibit the growth of scale crystals CaSO4 and reduce its crystallinity, but also could destroy the crystalline regularity to inhibit the scaling capability.