Abstract: A mobile device capable of offline and online synchronous image identifying is disclosed. The mobile device includes an image capturing unit, a processor, and a display monitor. The image capturing unit retrieves frames of a recognition target. The processor determines whether the mobile device is operatively connected to Internet. Also, the processor sends the frames to a recognition server via the Internet, and performs offline image recognition to the frames and displays the result of the offline image recognition on the display monitor when the mobile device is connected to the Internet, and receives a result of an online image recognition performed synchronously to the frames by the recognition server and displays the result of the online image recognition on the display monitor when the result of the online image recognition has a recognition value higher than a recognition value of the result of the offline image recognition.