The invention discloses a method based on an isolating device for achieving SOCKET transparent transmission between internal and external power networks. The method comprises the steps that: (1) a network module of a network proxy module is adapt to a SOCKET protocol, a network flow transmitted by a SOCKET is converted into a file flow according to set codes, and a file is generated and output to a specified directory; (2) the isolating device monitors file variation of the specified directory, inspects and checks the newly generated file, ferries a file conforming to internal and external power network transmission standard to other network regions, and forbids the ferry of a file not conforming to the internal and external power network transmission standard; (3) and a file module of the network proxy module monitors and reads the file ferried by the isolating device, decodes the file into original content, and converts the original content into a SOCKET request to be sent to a target application. The method provided by the invention can achieve SOCKET transparent transmission between the internal and external power networks efficiently and safely, can satisfy audio and video applications, and can provide bottom layer communication channels for other applications.