The core of EDI standard EDI is the standardization of the data format of the business to be processed. In essence, EDI needs an international unified standard and uses the same language to communicate. Because EDI is the communication between computers, taking EDI in commercial trade as an example, EDI delivers electronic files. Therefore, in order to enable computers of different business users to recognize and process these electronic documents, a standard that can be understood and used by all trading partners must be formulated according to the agreement. At present, there are two major international standard systems, one is the UN/EDIFACT standard which is popular in Europe and Asia and formulated by the United Nations Economic Commission for Europe (UN/ECE), and the other is the ANSI X. 12 standard which is popular in North America and formulated by the American National Standardization Committee (ANSI). The standard of EDI should follow the following two basic principles: 1) Provide a language that can be used by all parties who send and receive data, and the sentences used in this language are gender-neutral. 2) This standard is not affected by the type of computer, that is, it is suitable for data exchange between computers and independent of computers. To become the standard data format of EDI, three elements need to be defined: data element, data segment and standard message format. The current industry standards are: CIDX (chemical industry), VICX (department store), TDCC (transportation industry) and so on. They are all specifically applied to a certain department. The most popular and authoritative EDI standard in the world is UN/EDIFACT. The following is a brief introduction to this standard: UN/EDIFACT is called the United Nations electronic data exclusion rules for administration, commerce and transportation, which indicates that this standard is applicable to the administration, trade and transportation industries. The following are the main points of the three elements of the data format of the United Nations Organization for Standardization. Data elements are the basic units of electronic documents. There are thousands of standard data elements in the United Nations, all of which are listed in the data element catalogue. Each data element is uniquely identified by a four-digit number. The data element directory provides an identifier and a meaningful name for each data element as a brief explanation of the meaning of the data element. Finally, specify the type and length of the data element. Data elements are usually alphanumeric strings, and all types are nothing more than an (letters, numbers) or a (letters). Length is the number of characters. A data segment consists of a set of data elements. There are two kinds of data segments, one of which is called user data segment. It reflects the items with certain functions in the document. It is an intermediate information unit, corresponding to a column on a paper document, such as consignor and consignee. Another kind of data segment is called service data segment. Sometimes called a control data segment. It provides information services for electronic transmission.