The invention discloses a carbon dioxide capture system assisted by the combination of solar energy and geothermal energy. The system is mainly composed of a power plant generations system, a carbon dioxide capture system, a solar energy collector system and a geothermal energy system. Carbon dioxide in power plant flue gas is removed through the carbon dioxide capture system, and heat needed by a reboiler in the carbon dioxide capture system is provided by the combination of solar energy and geothermal energy; on the condition that solar energy is sufficient in the daytime, the heat of the reboiler is provided by the solar energy collector system; when solar energy is insufficient or at night, and the heat needed by the reboiler is provided with geothermal energy; by coupling solar energy and geothermal energy, stable operation of the capture system is achieved, reduction of output power caused by steam extraction of a power plant is relieved, defects caused by defects of renewable energy sources in the renewable energy source utilization process are overcome, the dual effects of carbon dioxide capture and renewable energy source emission reduction are achieved, and integrated development of renewable energy sources and a traditional power system is promoted.