A method for detecting a power failure type of an electronic device sets a shutdown flag as a first value when the electronic device is turned on, modifies the shutdown flag to a second value if a shutdown status of the electronic device is detected, and modifies the shutdown flag to a third value when the electronic device keeps the shutdown status for a predetermined time. The method further determines the power failure type of the electronic device according to a value of the shutdown flag when the electronic device is turned on the next time.