The invention relates to the field of automatic protection, in particular to a stable operation method of a self-service terminal during power outage. The stable operation method comprises an infrared induction device, a bank card reader, a paper ticket printer, a main display screen, a ups (Uninterrupted Power Supply) power outage emergency power supply and a master control industrial personal computer, wherein the master control industrial personal computer controls the bank card reader, the paper ticket printer and the main display screen to finish various operations of a user after a system is powered on; under a working state of the self-service terminal, in a process that the user finishes the operations, the master control industrial personal computer monitors the voltage data input of the ups power outage emergency power supply, and a power supply is used for coupling sensing equipment to obtain the power supply situation of current input mains supply; and after comprehensive analysis, the bank card reader, the paper ticket printer and the main display screen are controlled to make a corresponding protection measure. The stable operation method of the self-service terminal during the power outage comprehensively protects the self-service terminal equipment and avoids a phenomenon that user operation is affected since the equipment immediately shuts down after the equipment is damaged.