The invention relates to a method for degrading polypropylene with a high transformation rate by utilizing solar heat-electricity coupled driving. The method comprises the following steps of: (1) drying the polypropylene; adding a conducting material and mixing the conducting material with the polypropylene uniformly; and putting the mixture into a reaction unit; (2) inserting an electrolysis electrode into the mixed materials in the reaction unit, sealing the reaction unit and heating the sealed reaction unit by utilizing a solar heat collecting device; (3) after the temperature inside the reaction unit reaches a preset temperature, applying constant current or constant voltage to the mixed materials by utilizing a solar battery so as to implement electrolysis by virtue of the electrolysis electrode; and (4) stopping heating and electrolysis and cooling the reaction unit to end the degradation. By adopting solar energy for degrading the polypropylene, the method provided by the invention realizes green, clean and sustainable degradation of waste plastic and is higher in degradation efficiency.