A system for external display, comprising: a mobile device, comprising: a first communication module; a storage module configured to store at least a first interface displayed by the mobile device, a second interface and a third interface; a processing module connected to the first communication module and the storage module; the system further comprising a display device being a smartbook or a television, each of the smartbook and the television comprising: a second communication module configured to establish a connection with the first communication module; a display module connected to the second communication module; wherein, the first communication module and the second communication module are both WiFi modules, and are configured to establish a connection via wireless WiFi, the processing module is configured to generate an external display information and to broadcast the external display information through the first communication module; the second communication module is configured to acquire the external display information, and to transmit an identifier information of the display device to the processing module based on the external display information; wherein the identifier information of the display device comprises WFD, WiFi display, device information of the second communication module; and the WFD device information is a 2 bytes data with bits 0-13 being the existing bits having definition and bits 14 and 15 being reserved bits; characterized in that the identifier information of the smartbook is set on bit 14 of the WFD device information, and the identifier information of the television is set on bit 15 of the WFD device information; and the processing module determines whether the bit 14 or the bit 15 of the WFD device information is 1; when the processing module determines that the bit 14 of the WFD device information is 1, the smartbook is determined to be in accordance with the second interface, and the mobile device is configured to transmit the second interface to the smartbook to make the smartbook display the second interface; and when the processing module determines that the bit 14 of the WFD device information is 0 and the bit 15 of the WFD device information is 1, the television is determined to be in accordance with the third interface, and the mobile device is configured to transmit the third interface to the television to make the television display the third interface. a mobile device, comprising: a first communication module; a storage module configured to store at least a first interface displayed by the mobile device, a second interface and a third interface; a processing module connected to the first communication module and the storage module; the system further comprising a first communication module; a storage module configured to store at least a first interface displayed by the mobile device, a second interface and a third interface; a processing module connected to the first communication module and the storage module; the system further comprising a display device being a smartbook or a television, each of the smartbook and the television comprising: a second communication module configured to establish a connection with the first communication module; a display module connected to the second communication module; wherein, the first communication module and the second communication module are both WiFi modules, and are configured to establish a connection via wireless WiFi, a second communication module configured to establish a connection with the first communication module; a display module connected to the second communication module; wherein, the first communication module and the second communication module are both WiFi modules, and are configured to establish a connection via wireless WiFi, the processing module is configured to generate an external display information and to broadcast the external display information through the first communication module; the second communication module is configured to acquire the external display information, and to transmit an identifier information of the display device to the processing module based on the external display information; wherein the identifier information of the display device comprises WFD, WiFi display, device information of the second communication module; and the WFD device information is a 2 bytes data with bits 0-13 being the existing bits having definition and bits 14 and 15 being reserved bits; characterized in that the identifier information of the smartbook is set on bit 14 of the WFD device information, and the identifier information of the television is set on bit 15 of the WFD device information; and the processing module determines whether the bit 14 or the bit 15 of the WFD device information is 1; when the processing module determines that the bit 14 of the WFD device information is 1, the smartbook is determined to be in accordance with the second interface, and the mobile device is configured to transmit the second interface to the smartbook to make the smartbook display the second interface; and when the processing module determines that the bit 14 of the WFD device information is 0 and the bit 15 of the WFD device information is 1, the television is determined to be in accordance with the third interface, and the mobile device is configured to transmit the third interface to the television to make the television display the third interface.