Abstract: For quite a long time,on the basis of the age of the trilobite fossils,many geologists andorganizations have di-vided the Cambrian in the Mount Serteng area into three“series”-rank chronostratigraphic units and used them as a basic mapping unit.Evidently this does not meet the requirements for mapping by means of lithostratigraphic u- nits. In this paper the Cambrian of the study area for the first time into major lithostratigraphic units in light of the principle of multiple stratigraphic classification and two formations are set up in ascending order:the Semagou For- mation in the lower part and the Laogushan Formation in the upper part. This paper also describes the stratotype sections.