Disclosed are the cation polymers capable of removing their positive charges in oxidative conditions, preparation methods, and applications as gene delivery carriers. The oxidation-responsive unit is the p-(boronic acid or ester)benzylammonium, which upon oxidation eliminates p-hydroxymethlphenol and thus converts in a tertiary amine. Compared with the prior art, different from a common quaternary amination carrier, the synthesized charge reversal type gene delivery carrier for oxidative response of the present invention has a large quantity of positive charges and can well coat a DNA, but the positive charges can be removed under the condition of intracellular oxidation when the charge reversal type gene delivery carrier enters a cell, a charge reverse is triggered, the positive charges turn to negative charges, and the DNA is quickly released for transfection. The carrier is efficient, low in toxicity, and good in application prospect.
