This paper proposes an EDHM(event-driven hypermedia model), which focuses on the task of defining and realizing hypermedia link, object synchronization and user interaction involved in a multimedia presentation. EDHM can be divided into three layers, which are data layer, container layer and presentation layer. Based on an event-driven scheme, timeline is applied to instinctively specify temporal and synchronous relationships between objects, and interactive objects together with an embedded simple script language——EasyScript handle the synchronization and action of objects. With an efficient hypermedia link solution, EDHM is able to support very large scale distributed demonstration system. Multiple authors can work simultaneously on a large project, and EDHM is suitable for inconstant authoring environment. An authoring tool called “Ark” based on EDHM has been used successfully.