Disclosed are a method and a device utilizing barcode images to communicate between a mobile terminal and a backend server and a mobile terminal thereof, which can correctly decode a barcode image of any code format, ensure the security of user information, and provide services on the side of the mobile terminal in the absence of the backend server. The method of the present invention includes the following steps: registering as a user of the backend server through the mobile terminal; taking a picture of the barcode image by using a camera disposed in the mobile terminal; decoding the taken barcode image to obtain coding information; parsing the coding information to determine whether the barcode image is generated according to a preset coding rule; the mobile terminal extracting service information corresponding to the coding information; the mobile terminal sending a service providing request message to the backend server; and the backend server providing a service to the mobile terminal according to content of the service providing request message.