For the need of environmental protection, it is an urgent problem to find an alternative halon extinguishing agent suitable for civil aircraft. Among various fire extinguishing agents or systems that can be selected, water mist fire extinguishing system has become the most promising alternative to halon because of its advantages such as environmental protection, cleanness, high efficiency, stability and non toxicity. Firstly, the fire extinguishing mechanism and unique advantages of the water-mist fire extinguishing system were introduced, as well as the Minimum Performance Standard (MPS) and test results formulated developed by International Aircraft Systems Fire Protection Working Group (IASFPWG). The research shows that the water mist fire extinguishing system meets the requirements of MPS well. In addition, the factors affecting the performance of the water mist fire extinguishing system were studied and analyzed; Increasing the working pressure and flow coefficient can effectively improve the fire extinguishing ability of the water mist fire extinguishing system, and the fire extinguishing performance of the water mist fire extinguishing system can be improved by adjusting the spray cone angle and droplet size; Adding a certain concentration of salt compounds and surfactants can also improve the fire extinguishing ability of the water mist fire extinguishing system, and different additives have different optimal concentration ratios.