A file management method and a file system are applied to the field of data processing technologies. The file system monitors input/output (IO) access information for operating a file, then determines an IO access mode of the file, determines a corresponding file management policy according to the IO access mode, and finally, when the obtained file management policy is inconsistent with a current management manner of the file, adjusts, according to the determined file management policy, the current management manner of the file, for example, a storage medium and a file management granularity, so as to dynamically adjust the storage medium and the file management granularity of the file according to the IO access mode of the file.