A data storage device includes a memory device and a memory controller. The memory controller configures a first predetermined memory block and a second predetermined memory block as buffers to receive data from a host device and determines to use the first or the second predetermined memory block to receive the data according to write addresses of a write command received from the host device. When the write addresses indicate that the data to be written by the host device is management data of a file system of the host device, the memory controller writes the data to the first predetermined memory block. When the write addresses indicate that the data to be written by the host device is not the management data of the file system of the host device, the memory controller writes the data to the second predetermined memory block.