A method for information backup, including that: detecting, by an information backup device, a battery volume of a mobile terminal and determining whether the battery volume reaches a preset low-battery alarming threshold; and storing, by the information backup device, contact information stored in the mobile terminal into a backup memory card when the battery volume reduces to the low-battery alarming threshold; characterized in that, after the step of storing, by the information backup device, contact information stored in the mobile terminal into a backup memory card, the method further includes: detecting, by the information backup device, the battery volume of the mobile terminal and determining whether the battery volume reaches a preset emergent contact display threshold which is smaller than the low-battery alarming threshold; shutting down, by the information backup device, the mobile terminal when the battery volume reduces to the emergent contact display threshold; and controlling, by the information backup device, the mobile terminal to enter into an emergent contact display mode to display contact information on the screen of the mobile terminal after a launching instruction input by a user is received to start a startup flow when a power button is pressed by the user, wherein the mobile terminal consumes less power when in the emergent contact display mode than when running normally. detecting, by an information backup device, a battery volume of a mobile terminal and determining whether the battery volume reaches a preset low-battery alarming threshold; and storing, by the information backup device, contact information stored in the mobile terminal into a backup memory card when the battery volume reduces to the low-battery alarming threshold; characterized in that, after the step of storing, by the information backup device, contact information stored in the mobile terminal into a backup memory card, the method further includes: detecting, by the information backup device, the battery volume of the mobile terminal and determining whether the battery volume reaches a preset emergent contact display threshold which is smaller than the low-battery alarming threshold; shutting down, by the information backup device, the mobile terminal when the battery volume reduces to the emergent contact display threshold; and controlling, by the information backup device, the mobile terminal to enter into an emergent contact display mode to display contact information on the screen of the mobile terminal after a launching instruction input by a user is received to start a startup flow when a power button is pressed by the user, wherein the mobile terminal consumes less power when in the emergent contact display mode than when running normally. detecting, by the information backup device, the battery volume of the mobile terminal and determining whether the battery volume reaches a preset emergent contact display threshold which is smaller than the low-battery alarming threshold; shutting down, by the information backup device, the mobile terminal when the battery volume reduces to the emergent contact display threshold; and controlling, by the information backup device, the mobile terminal to enter into an emergent contact display mode to display contact information on the screen of the mobile terminal after a launching instruction input by a user is received to start a startup flow when a power button is pressed by the user, wherein the mobile terminal consumes less power when in the emergent contact display mode than when running normally.