We propose a new layout method using Magnetic Spring Model for object diagrams used in OMT. In our new method, there are two main characteristics.Firstly, our new method considers the interactive layout. User can use the layout function many times during drawing the diagram. The result of the layout is suitable to continue to draw the diagram smoothly. Secondly, our method can avoid overlapping of nodes with new definition of the distance between nodes.We have implemented the new layout method to the object diagram drawing CASE tool. We compare the result of the new layout method with the result of the old layout method. We have made sure that our new layout method is more suitable for the interactive layout than the old layout method and avoids the overlaps of nodes.