Abstract: The mega frame-core tube structural system and its foundation of super tall buildings are simplified equivalently and continuously into a bundle of stiffened-thin-wall tubes on semi-infinite elastic subgrade. A three-dimensional semi-analytical model considering the interactions between the ground, the foundation and the superstructure is then developed. Consequently, the model is applied to analyze the mega frame-core tube structural system for super tall buildings by the semi-analytical method. The analyzing result shows that the analytical model is reasonable and effective.