A BIOS module for automatic restoring and the related method are provided. The BIOS module has a BIOS memory and a prime BIOS code embedded therein. When the contents of a BIOS memory is damaged, a backup BIOS code can be loaded from other storage media for rebooting the computer system. The BIOS code comprises a BIOS function program module having a compressed function program, a detecting means for detecting the correctness of the BIOS function program module, a restoring module responsive to the detecting means for automatic rebooting the computer when the decompressing procedure has errors to load and execute the BIOS backup code from other storing media. And after rebooting the computer system successfully the restoring module also can restore the BIOS backup code into the BIOS memory. Besides, a differentiating means is applied to check the versions of the backup BIOS code and the prime BIOS code. When the prime BIOS code can boot the computer system successfully and the version thereof is latest than that of the backup BIOS code, the prime BIOS code can be backuped to the storage media.