Method and device for cross-network safe transmission

The invention relates to a method and a device for cross-network safe transmission. The method comprises receiving data flow from a network Na and selecting a data packet with an expanded-name appointed; partitioning and organizing data according to content identification and order identification of the data packet; converting the data to a corresponding character string; converting the character string to a two-dimension code pattern and displaying the two-dimension code pattern on a display screen; scanning and receiving the two-dimension code by a scan head, analyzing the two-dimension code to be the corresponding character string, converting the character string into the data packet with the expanded-name, the content identification and the order identification and sending the data packet to a network Nb. According to the method and the device for the cross-network safe transmission, two sides offering communication adopt an anti-diffusion wireless-connected communicating method and adopt a self-defined communicating protocol to achieve interconnection and intercommunication of two independent networks instead of adopting a traditional public wireless network communication protocol, and therefore independence of the two communicating networks can be guaranteed completely , the shortage that the traditional network communication protocol is lack of safety is overcome and safety factors of internet communication are greatly increased.