The invention discloses a liquefied carbon dioxide energy storage system and application thereof. The liquefied carbon dioxide energy storage system adopts carbon dioxide as an energy storage medium,an artificial container can be used more flexibly, the energy density of the system is improved, the system forms a closed loop, and greenhouse gas can be prevented from being released to the environment; and on the other hand, the liquefied carbon dioxide energy storage system can achieve power grid frequency modulation and peak load shifting, and the renewable energy utilization rate is increased. The liquefied carbon dioxide energy storage system comprises a first compressor, a first cooler, a first hot tank, a first cold tank, a second heater, a first expander, a third expander, a cold regenerator, a throttle valve, a first liquid carbon dioxide storage tank, a second cold tank, a third cooler, a third heater, a second hot tank, a fourth heater, a fifth pump, a third cold tank, a second liquid carbon dioxide storage tank, a third hot tank, a separator, a fourth expander and a fourth cooler.