A disk managing method includes: receiving a host Frame Information Structure (FIS) including multiple host logical Block Address Range Entries (LBA Range Entries) from a host; determining whether the LBA Range Entries satisfy a speed up processing condition; generating a first and a second addresses corresponding to a first and a second hard disks according to the host LBA Range Entries; and outputting a first and a second hard disk FIS to the first and the second hard disk for management. The number of first and second hard disk LBA Range Entries in the first and the second hard disk FIS are respectively half of the number of the host LBA Range Entries.