Abstract: In order to further improve the water environmental quality and water treatment efficiency, it is particularly important to develop a new type of water treatment agent with high efficiency. As a common water treatment agent, the polymer can capture a variety of pollutants through electrostatic force and hydrogen bond due to its own polymerization characteristics, thus the polymer can separate the pollutants from water efficiently. Hyperbranched polymer (HBP) is highly branched polymer with three-dimensional structure and high macromolecular weight, and with many branching sites and abundant terminal functional groups. Also, the molecular chain of HBP is hard to tangle and easy to be grafted, so it can synthesize new functional materials. In this review, according to the different terminal functional groups of HBP, the synthesis and preparation of three kinds of HBP (amino hyperbranched polymers, hydroxyl hyperbranched polymers and carboxyl hyperbranched polymers) were reviewed, then the graft modification and application of HBP in water treatment were also reviewed. Due to the three-dimensional macromolecular structure and abundant terminal functional groups of HBP (—NH₂, —COOH, —OH, et al), HBP and its graft modified products exhibit excellent performance in polluted water (heavy metal wastewater, dye wastewater, oil-bearing wastewater, et al). In the future research, the graft modification of HBP can be further studied to prepare new hyperbranched composites, thus the recycling and reuse performance, water treatment efficiency of hyperbranched composites can be enhanced, the water treatment cost can also be reduced. This research of HBP and the new hyperbranched composites will provide useful theoretical basis and technical support for the development of new environmentally friendly water treatment agents.