According to the analysis of newly compiled 1:2 000 000 gravity and magnetic data,there exist three (eastern,central and western) deep tectonic areas in northern China,which are bounded in the east by Helan Mountain Liupan Mountain Longmen Mountain line and in the west by Xingxingxia Ruoqiang line.It can thus be seen that the eastern area covers North China Northeast China area,the central area comprises Inner Mongolia Gansu Qinghai area,and the western area is Tarim Junggar area.The eastern and western parts consist of two oldest Archean Early Proterozoic stable land masses of China,whereas the central part is the Proterozoic land mass,which is rather active due to the compressive action of Qinghai Tibet plateau.It is also held that the original boundary,namely Da Hinggan Mountains Taihang Mountains Wuling Mountain fault,exists merely in the eastern tectonic area and does not form the boundary separating various areas.