A computer architecture with multiple operating systems (OS) using a common disc partition and a method for the same are proposed. The computer architecture includes: a first operating system having a file system used to store a second operating system; a random access memory (RAM) disc, wherein the RAM disc is a virtual storage device composed of partial memory of a memory unit and the second operating system can be executed in the RAM disc; and a basic input/output system (BIOS) used to control a booting procedure of a computer system and load the second operating system into the RAM disc. Therein, the second operating system can use parameter information and a multimedia playback system of the first operating system directly via an interface unit.