Electronic business document interoperation is the cornerstone of business process integration. An essential issue for business document interoperation is to maintain semantic consistency of the exchanged business documents between any two autonomous business communities, where the document sender and receiver have no misunderstanding in using the exchanged documents. Existing approaches to resolving this issue either adopts document standards to map heterogeneous document elements or applies business ontologies to mediate inconsistent document elements. While these approaches are effective in certain degree, the issues of limited flexibility and evolvability in using standards and the lack of accuracy in using ontologies to mediate document elements must be explored and resolved. This paper proposes a Collaborative Document Exchange (CODEX) approach to resolving the issues. In this approach, structures and concepts of business document are separated and layered in CODEX framework. Structures provide the commonality of business documents through classified concept identifiers while concepts support particularity of business documents through collaboration.