Abstract: The new solid-state supercapacitor has higher mechanical stability, easy operability and temperature and weather resistance, neither the traditional solid-state electrolyte is easy to leak, not easy to carry the shortcomings, nor the liquid polymer electrolyte is easy to corrosion, easy to explode risk, is a high-power energy storage supercapacitor with great market prospects. Solid state supercapacitors require electrolyte ion mobility, high conductivity, good activity and high mechanical stability. Gel polymer electrolyte is the most suitable electrolyte in solid polymer electrolyte because of its high safety, good stability and natural pollution-free characteristics. According to the different sources of electrolyte base, it can be divided into two types of natural and synthetic polymer electrolytes. The composite polymer electrolyte is mainly composed of polymer base, additives and electrolyte salts. The composite polymer electrolyte acts as both a conductive medium and a diaphragm in the supercapacitor. In this paper, the characteristics of different polymer electrolytes are reviewed, and the influence and mechanism of polymer electrolytes on the energy storage and electrochemical performance of supercapacitors are described. Finally, the challenges and future development focus of building efficient energy storage systems are put forward.