Abstract: The lack of safe and efficient gene vectors restricts the development of gene therapy. In this comprehensive experiment, three cationic polymers were designed and synthesized by epoxy ring-opening polymerization and used as gene vectors. The hydroxyl groups formed by epoxy ring-opening reaction were uniformly distributed on the backbone of the polymers. The polymers also contain aliphatic chains or aromatic rings, which are used to adjust the rigidity of the polymer and synergize the hydroxyl groups to adjust the hydrophilic/hydrophobic balance. The structure of the polymers was characterized by ¹H NMR and GPC. Then, the DNA binding ability, cytotoxicity, protein adsorption capacity and transfection efficiency of the polymers were studied, and the preliminary structure-activity relationship of gene vectors based on epoxy ring-opening polymerization was further obtained.