The invention relates to the application field of intelligent cards and provides a non-contact intelligent card file system for supporting power fail safeguard and a method for preventing power fail. The file system provided by the invention is as follows: a power fail safeguard area is additionally arranged on the basis of a traditional chain file system; the traditional chain file system comprises a main file, a special file and a basic file and the main file and the special file in the traditional chain file system are connected with the power fail safeguard area through an indicator of the power fail safeguard area. The system provided by the invention can be compatible with the traditional chain file system and also can protect the operation data of the file system; the data structure of the power fail safeguard area can supply powerful guarantee and rapid data recovery to the operation stability of the data of all intelligent cards; in addition, by using the method for preventing power fail, the stability of reading and storing the data of the non-contact intelligent card is also greatly improved; and the system provided by the invention can be widely applied to multiple non-contact intelligent card applications, such as bus cards, social security/tour and the like or can be used for a one-card and multi-application intelligent card service.