Abstract: Due to the popularity of computers and the rapid development of Internet, the diversification of information exchange and utilization causes the standardization of information to become more and more imperative. Based on the problem of document structuring and by applying the standardized language for information exchange （SGML/XML）, the design of document type definition （DTD） is described, and the structure directed method is used to implement a document editor so as to generate automatically the structured document which conforms to DTD.