Abstract: According to the characteristics of hierarchical objects, we presented a level of detail (LOD) method for intelligent display control via zooming in and zooming out. At first, the conception of angular resolution of eye and the rate of objects overlaping is proposed based on the human-eye simulation, then the rule of roll-up and drill-down along the hierarchy tree is described. At last, the LOD method for an intelligent display control is discussed. This method is very suitable to hierarchical objects of large data set. It is implemented in an experimental command, control, communications & intelligence (C3I) system, and its display effect is shown.