The invention discloses a method and a system for utilizing carbon dioxide in exhaust flue gas and energy of a thermal power plant based on a plant factory. The method includes the steps that the plant factory is built near the thermal power plant; low quality heat from the thermal power plant, such as hot water or steam, can be used for supplying heating to the plant factory, and the steam also can be used for driving chillers to produce chilled water to cool the plant factory; the carbon dioxide in the flue gas of the thermal power plant is inlet into the plant factory and used for absorption and utilization as gas fertilizer; the thermal power plant can also be used for directly supplying power to lighting system of the plant factory. The method integrates the thermal system of the thermal power plant and the air conditioning system of the plant factory, thereby providing a new scheme for the energy saving and emission reduction of the thermal power plant.