The invention relates to a method and a system for supplying energy by taking carbon dioxide as a carrier. The system comprises a dry ice manufacturer, a dry ice storage tank, a liquid carbon dioxide pump, a compressor and a low temperature fan, wherein the dry ice storage tank is connected with an inlet/outlet of the dry ice manufacturer; the dry ice storage tank is connected with a low-temperature liquid carbon dioxide generating device through a carbon dioxide liquid pipeline; the dry ice storage tank is connected with a low-temperature carbon dioxide user and/or the low-temperature liquid carbon dioxide generating device through a low-temperature carbon dioxide gas pipeline; liquid carbon dioxide is prepared into dry ice by the dry ice manufacturer and the dry ice is conveyed to the dry ice storage tank for storage; the low-temperature liquid carbon dioxide is sent to the low-temperature liquid carbon dioxide generating device for low-temperature generation; low-temperature carbon dioxide is sent to the low-temperature carbon dioxide user and/or the low-temperature liquid carbon dioxide generating device through the low-temperature carbon dioxide gas pipeline. According to the system provided by the invention, carbon dioxide is taken as working medium, the system is used for low-temperature generation and other low-temperature purposes, the energy is efficiently stored and utilized and the flexible adjustment and utilization for the energy can be realized.