The fuel tank flammability reduction means design for civil aircraft is an important part of fuel tank explosion proof design, it is necessary to carry out the related research. By studying the 25. 981 airworthiness requirements for civil aircraft, this paper summarizes the fuel tank flammability requirements and the corresponding FRM(flammability reduction means), and also studies the applicability of cooling mechanism based on FRM. The results show that this concept has some limitations in actual application, especially it can′t meet flammability airworthiness requirement for the fuel tank within the fuselage configuration.