This paper describes how to present different multimedia objects on a Multimedia Abstract Machine with a structural mechanism. The structural mechanism is based on a timed Petri net. We use the features of a Petri net to display the behavior of multimedia objects and to introduce the concepts of navigation messages of users in the timed Petri net model. The paper will explain the algorithm of our model. The main goal of this structural mechanism provides a feasible method to represent a schedule and the navigation of different multimedia objects with navigation messages of users. Users only input a Data Flow Diagram and a Control Flow Diagram to the Multimedia Abstract Machine, and the system will display all situations of multimedia presentation. Users can dynamically change requests to result in different results during the multimedia presentation. Our system constructs a structural mechanism and a better user interface. Using our system, a multimedia presentation designer can design and analyze his/her multimedia presentation.