Abstract: It is analyzed that random vibration spectrum and time history curve of reflection of mega-sub controlled structural system subjected to seismic loads. It is also observed that this new kind of structural system holds more merits of resisting seismic forces. The seismic reflections of the structure may be depressed further, when dampers are appropriately fixed in the sensitive part of the structure, which makes the best of dissipation capacity of dampers and can not weaken tuned advantage of subframes. For this new building system, viscous dampers are proposed, which can easily be actualized in practical engineering, can not change natural frequency of structure and produce prominent controlling effect.