Abstract: A computer document that links up a user and a system is one of the most important parts of a software system and a supplementary of the user interface of software. In accordance with the present situation of the development of computer documents, especially user documents, it is emphasized in this paper that user document is important to usability of software and a user interface of the document is important to usability of a user document, and we introduce the concept of a document life cycle design method for the document structure and the user interface.