The external storage pressure type heptafluoropropane fire extinguishing system stores the heptafluoropropane fire extinguishing agent in a liquid state in a container without nitrogen pressure. The pressure is stored in another container. When the system is working, the high-pressure power gas is decompressed through the pressure reducing valve and then injected into the fire extinguishing agent storage bottle (at the same time, the bottle head valve of the container bottle is opened), and the power gas pushes the fire extinguishing agent (through the siphon, the bottle head valve) along the pipe network system at high speed. Move forward and spray fire at the sprinklers in the protection zone. Since the fire extinguishing agent and motive gas are stored in different containers, two problems can be solved: - the fire extinguishing agent is not stored in contact with nitrogen, and the gas will not be dissolved in the fire extinguishing agent due to the use of nitrogen pressurization; After the system is started, the pressure during the delivery and discharge of the fire extinguishing agent is always higher than its storage pressure, and there will be no precipitation of the fire extinguishing agent vapor and nitrogen, which effectively alleviates the dual-phase flow phenomenon during the delivery of the fire extinguishing agent. Therefore, the flow state of the fire extinguishing agent is stable during the transportation process, and the power gas is always at the end of the fire extinguishing agent, which pushes the liquid fire extinguishing agent to move rapidly in the form of a single-phase fluid in the pipeline, and its speed is faster and more stable than that of the storage pressure system. The ability of pipelines to transport fire extinguishing agents is improved, thereby extending the transport distance, increasing the spray pressure of fire extinguishing agents, and realizing the use of thinner pipes to transport more fire extinguishing agents.