In this paper, we introduce a new idea of Revision Tree which can provide a flexible mechanism to store the current collaborative virtual environments (CVE) space, replay the past recorded CVE space and replace the current CVE by other past CVE space. Revision Tree with hierarchical 3D structure is visualized in space and operated by users to refer the past space information using replay, revert, clone and merge functions. Those functions provide effective and flexible collaborative work in CVE to support communication among many users over computer network. Using this method, the users as group members can progress collaborative work and confirm the past CVE without prior communication even if some of the group members do not participate in the space. Thus, asynchronous collaborative work can be attained and applied to efficiently more creative CVE applications.