An important modelling requirement for multimedia systems is the representation of temporal constraints among several different media that ordinarily arise in multimedia application. The multimedia system which integrates various types of data is required to express voice, image, text and graphic data with simultaneousness or an arbitrary time intervals. The purpose of this study is to analyze the temporal reationships and synchronization among several different kinds of medium. Moreover, it proposes a Multimedia Display-Time Composition Model (MDTC Model) which guarantees a representation of any kind of temporal synchronization among more than two kinds of medium. The proposed model is applied to a company advertizing system. Finally, a multimedia authoring tool based on the MDTC Model is implemented.