An electronic device and a method for controlling a sharable cache memory of the electronic device are provided. The electronic device includes a central processing unit including at least one core processor, at least one module, and a sharable cache memory including a controller, wherein the controller enables the sharable cache memory as a cache memory of the central processing unit if the central processing unit is in a working mode, and wherein the controller enables the sharable cache memory as a buffer of at least one of modules if at least one core processor of the central processing unit is transitioned to a sleep mode.