The paper proposes a conference control model between a web server and a telecom application server,referred to as the Conference Directed Graph(CDG) ,and describes an asynchronous communication mechanism between them. The Corba Interface Definition Language(IDL) interfaces are defined,and a message sequence chart is illustrated. This web conference control model provides conference users with a new approach to manage and control a conference and the participants. The performance of the system prototype is analyzed and verified in the 863 project named "The Multi-media and Mobile Services Enabled Soft-switch System".