A method for performing data access control of a memory device with aid of a predetermined command and associated apparatus are provided. The method may include: utilizing the memory controller to receive a first single command from a host device through a transmission interface circuit of the memory controller; and in response to the first single command conforming to a predetermined format of the predetermined command, utilizing the memory controller to perform a series of operations according to the first single command, wherein the first single command represents a first duplicate command, for duplicating from a first source logical address to a first destination logical address. The series of operations may include: reading first data at the first source logical address; and writing the first data at the first destination logical address.