The collaborative authoring of multimedia documents poses some special requirements of the structure and synchronization of documents. In order to make the object-oriented implement of these documents easy and multiple granularity sharing of them flexible

we propose here a synchronization model for complex distributed interactive multimedia document in collaborative authoring tools. This hierarchical mode consists of three layers: page

object group

and medium object layer. Considering the characteristics of these layer

the synchronization of them are of jump-based

event-based

and time-based mode respectively.