Abstract: The basement of Mesozoic Erlian basins is a fold of late Palaeozoic.Numerical palaeo-terrains were separated duing several cleavages and closures between Siberia and Sino-Korea palaeo-plates;and epicontinental sea sedimentation was dominant in middle and lower Carboniferous and lower Permian.On the whole,there were brittle masses enveloped in ductile folding belts with different rigidities and low consolidation.It was very influential on the formation of Mesozoic continental basins.No centralized catch basin appeared during Mesozoic,but the basin-range structures in the form of basin group were marked.During the evolutional stages of comp-ressional rising,stretching rifting deppression and compressional rising,the stretching rate of faulted subsidence was only about 20%,while the violent remoulding took place in later period,and basins(faulted subsidences)can be divided into two types and six subtraps.Seven original types were recognized for secondary structural belts with different evolutional histories,resulting in differences in the generation,accumulation and preservation of hydrocarbons.