Given the remarkable development of multimediaand computer technology in the information age, the previousdominant role of language in mass media and communication ischallenged by other semiotic resources such as image, sound andaction. Accordingly, new grammars must be formulated to give acomprehensive account of the integrative meaning generated bythe interaction of different modalities in discourse. The theory ofmultimodal discourse analysis (MDA), which is theoreticallybased on Systemic-Functional Linguistics, solves the problem tomost degree. In the light of the grammar of visual design byKress and van Leeuwen, this paper intends to formulate a modelfor MDA of movie posters. A qualitative and interpretativeapproach is used to hold an in-depth discussion which helps totestify the feasibility of this model and also to point out the key tothe application of this model. The present study may not onlyenlarge the application area of Systemic-Functional Linguistics,but also fill in a gap in discourse analysis of movie posters