Even though its advantages such as non-volatility, fast write access time and solid-state shock resistance, NAND flash memory suffers from out-place-update, limited erase cycles, and page-based I/O operations. How to provide fast mounting and consistency of file system and data for flash memory file systems has become important research topics in recent years. In this paper, we design and propose a new flash memory file system called RFFS (Reliable Flash File System), which targets NAND flash memory based embedded systems that require fast mounting and fault tolerant file system. We have experimented on the performance of RFFS and the results showed that RFFS could improve the mounting time by 65%