A memory control device includes a memory and a controller. The memory includes a plurality of memory blocks. The controller is coupled to the memory and configured to select a first memory block from the memory blocks and program data into the first memory block. When the memory control device is deactivated and re-activated, the controller is further configured to read a voltage distribution of the first memory block to determine a deactivation interval, and determine a reference time according to the deactivation interval and an initial time, and the voltage distribution of the first memory block correspond to the data.