This study investigated the development of preschoolers' drawing compositions of complex three-dimensional structures. The task was to draw two kinds of complex threedimensional structures by tactile exploration first. and then by visual exploration. On assumption that children will employ such drawing strategies as to combine diagrams which correspond to sides of the structure, drawing compositions were analysed by angles from which sides of the structure were drawn (angles of drawing diagrams) and by the combination forms of diagrams. As a result, most of the 5-year-old children utilized diagrams corresponding to orthogonal projections of particular sides of the structure and combined them as if the structure were seen from multiple viewpoints. On the other hand, 6-year-old children utilized diagrams corresponding to orthogonal projections of several sides of the structure and combined them as if the structure were seen either from multiple viewpoints or from a single one. This study suggested that preschoolers were gradually able to employ several drawing strategies properly according to different contexts.