The invention discloses a power cut memory system. The power cut memory system comprises a power cut memory device and an electronic device. The power cut memory device comprises a switch receiving a direct voltage, an energy storage module and a processor. The switch is switched between an on-state and an off-state according to a control signal to determine whether to provide a voltage related to the direct voltage through an output end. The energy storage module generates a judgment voltage according to the on-state or the off-state of the switch, and the judgment voltage changes along with the voltage of the output end of the switch. The processor is electrically connected to the energy storage module and the switch, generates the control signal and comprises a non-volatile memory storing working data of the electronic device before a power cut; in power restoration of the system, the processor reads the judgment voltage to determine whether to read the working data and generates an action command, and the electronic device receives the action command of the processor and operates in a working mode or a standby mode according to the action command. The invention further discloses the power cut memory device. The power cut memory system and the power cut memory device have higher stability and higher safety.