This paper deals with the multimedia data presentation model, which is one of the palticular problems of multimedia databmm systems. First, the characteristics of mul-timedia data are discussed. Secondly. the existing multimedia data models are analysed. And then the method of concept and presentation modelling is explained, and the schema architecture of a multimedia database system is described. Finally, the problem of spatio-temporal composition of multimedia objects is discussed. and a multimedia data presentation model, namely, Multimedia Object Play-Out Model (MOPOM). is defined.