Abstract: Horizontal and vertical locations of nodes and orthogonal arrow lines between nodes are analyzed when activity-on-node network is drawn, and computational formulas are given to calculate them. A model to layout activity-on-node network is proposed. Interface software is then developed to make it possible for the model to communicate with the software Access and AutoCAD, which improves greatly the data management, maintenance and graph output quality. More information is read from activity-on-node network by using rectangular marks to represent nodes.