The present invention relates to the method for managing directories of a large-scale file system. The present invention the steps of creating root blocks which have a fixed global depth, calculating an index value which shows the location information on how many bits will be referenced for root blocks from the global depth through a hash function when root blocks are completely filled with directories, calculating the block numbers of leaf blocks consisted of extent blocks based on a plurality fixed length platform which are logical and successive objects using the index value and storing the block numbers sequentially to the root blocks, and storing the directory entries of root blocks separately in leaf blocks. As a result, the present invention can improve the search performance by minimizing the cause of frequently change of data storage structure of the file system and flexibly preventing creation of indirect blocks.