How to mine hot dry rock， which is a kind of renewable clean energy， is of great significance； however， both the temperature and depth of hot dry rock makes it difficult to exploit hot dry rock geothermal resources. In the mining process， reservoir construction is one of the key technologies. Reservoir construction produces a large-scale volumetric fracture network to ensure a large area of heat exchange channels for long-term thermal energy extraction. As a new method， the carbon dioxide blasting fracturing technology provides new ideas for reservoir construction. This paper briefly describes the carbon dioxide blasting fracturing technology， as well as the internal relationship between the amount of carbon dioxide charged， the amount of activator， and the thickness of the rupture disc during the blasting process. The carbon dioxide fracture initiator used in the construction of hot dry rock geothermal reservoirs is optimized. The specific parameters of the internal structure of the initiator have been designed， and the external structure and overall system have been improved. Finally， a new type of carbon dioxide initiator that can be used in the construction of hot dry rock geothermal reservoirs is developed， which provides effective technical means for the construction of hot dry rock geothermal reservoirs， and fills the gap in the field of downhole carbon dioxide fractur initiators that are resistant to high temperature and pressure.