A memory controller and a method for accessing a memory module are provided. The memory controller is coupled between the memory module and a host controller to control the access of the host controller to the memory module. The memory controller comprises: a central buffer coupled to the host controller for receiving a data access command from the host controller, and coupled to the memory module for providing a modified data access command to the memory module; wherein the central buffer comprises an access command processing module, for processing the data access command to generate the modified data access command; and a data buffer coupled to the central buffer for receiving the modified data access command from the central buffer, and coupled between the host controller and the memory module for exchanging data between the host controller and the memory module under the control of the modified data access command.