The Ordovician in Ordos was identified with a comprehensive method of integrating the outcrop sections, well sections and seismic profiles. Totally 213 pie
ces and 8317 km of seismic profiles were disposed and stratigraphically interpre
tated, which greatly upgraded the interpretation of the seismic profiles. Based
on above achievements, the Ordovician in Ordos was divided into 10 stratigraphi
cal units, i.e. Yeli Formation, Liangjiashan Formation, Majiagou Formation Ⅰ, Majiagou Formation Ⅱ, Majiagou Formation Ⅲ, Majiagou Formation Ⅳ,  Majiagou Formation Ⅴ, Majiagou Formation Ⅵ, Pingliang Formation and Beiguoshan Formation.Their isopach maps were compiled. These maps show that the palaeotectonics
of Yeli Age and Liangjiashan Age was in the style of one uplift and three depressions, i.e. o
ne middle uplift was surrounded by western depression, southern depression and ea
stern depression, which took the shape of “U". The palaeotectonics of Majiagou
Age Ⅰ to Majiagou Age Ⅵ shaped up one uplift and three depressions, although the shape, size and location of uplifts and depressions were changeable. The palaeo tectonics of Pingliang Age was in the shape of one uplift and two depressions, i.e. the enormous Ordos uplift was edged with the western depression and southern depression, which took the shape of “L". The  palaeotectonics of Beiguoshan Age was in the shape of one u
plift and one depression, i.e. the residual southwestern depression was located at the southwestern corner of the more enormous Ordos uplift. At the end of Ordov
ician, the Ordos and the whole North China Platform came into an unified uplift
and the framework of uplifts cooperated with depressions vanished.