The application discloses an apparatus for monitoring data access to internal memory device and an internal memory device. The internal memory device is coupled to a memory controller via a memory bus. The monitoring apparatus includes a buffer memory module and a security control module. The buffer memory module is configured to couple with the memory bus to receive and store data exchanged via the memory bus and/or a data access command and a destination address associated with the exchanged data. The security control module is configured to process the exchanged data and/or the data access command and the destination address stored in the buffer memory module to identify the existence of security risk in the data access to the internal memory device. The monitoring apparatus will not affect the operation of the internal memory device, and thus is fully compatible with the conventional system architecture. Moreover, by monitoring the data access to the internal memory device, potential security risks can be identified to improve the security and stability of the system.