The invention relates to a monosubstituted obaltocene cationic derivative and a high-efficiency preparation method. The preparation process is completed in one step by a one-pot method; an expensive catalyst is not needed; the operation is simple, easy and feasible; the reaction condition is mild; the reaction efficiency is high; the column separation is not needed; the post treatment is simple, convenient and quick, and the target monosubstituted obaltocene cationic derivative can be applied to the fields of novel surfactants, novel polyelectrolyte materials, antibacterial materials and fuel-cell diaphragms, and the like.