Security protection for memory content of processor main memory

The invention relates to memory device and the security thereof, particularly the security protection for the memory content of a processor main memory. The security protection method comprises the steps of: receiving the write-in instructions via a main memory which can be accessed by a processor; receiving the write-in instructions via the controller of the first memory; confirming the verification of the write-in instructions, with a second controller of the main memory being used for the confirmation; and deciding whether to modify the content of the main memory or not partly based on the verification of the write-in instruction. The disclosed memory can prevent the content be modified or accessed without authorization or be verified.