Computer aided instruction is an indispensable modern teaching method. How to make multimedia technology and traditional teaching methods complement each other to form an organic wholeness, and give full play to the advantages of multimedia technology is now a new research spot. In this paper, the characteristics of multimedia teaching method are analyzed in terms of advantages and disadvantages. Base on the bridge engineering course, the design method of multimedia courseware is introduced in terms of design basis, concept, teaching mode design, multimedia data embedding technology and so on. Problems deserving of attention in designing of the multimedia courseware such as the relationship between modern and traditional teaching method, matching of courseware and teaching points are also discussed in this paper.