Carbon dioxide capture，utilization and storage（CCUS）technology is of great significance for the mitigation of climate change. However，CO2 leakage may occur during gas injection and storage. The failure of wellbore integrity is the main way of CO2 leakage. At present，the research of wellbore cement integrity is mostly about the modification of anticorrosive cement system or cement squeezing. Thus，choosing polymer gel with better inject ability，stronger stability and lower cost can prevent and repair the failure wellbore. Smart polymer gels are currently receiving widespread attention，which can respond intelligently to changes in the formation environment. When the pH of the formation changes，the hydrogel will swell and expand，and the shape will become larger，thereby achieving effective sealing of the failure cement. The research progress of sealants for carbon dioxide geological storage was introduced in detail in this study，and the sealing mechanism and sealing performance of pH-responsive gels were critical reviewed，and then the future development direction and application prospects were discussed as well.