An electronic device having updatable BIOS is used to perform a BIOS updating method. The electronic device electrically connects to a server, in which update data is stored. The electronic device includes a Basic Input/Output System (BIOS), a network connection module and a switch. A BIOS program is stored in the BIOS, and a connecting program is stored in the network connection module for connecting to the server. When the electronic device is updating, the BIOS switches to electrically connect to the network connection module via the switch, and the network connection module connects to the server by executing the connecting program, downloads the update data applying to the BIOS, and overwrites the update data to the BIOS to update the BIOS program.