Abstract: Through the 1∶50,000 regional geological survey of the Ji’an Taihe basin,the authors put forward the structural lithological lithofacies mapping method.First,determine structural unconformities and facies change surfaces and preliminarily establish the lithostratigraphic units group and formation on the basis of an analysis of regional data and subsequent reconnaissance.Second,construct the section and intensively study all kinds of lithostratigraphic surface and the internal structures of the rocks and strata bounded by these surfaces in order to establish the groups,formations and members as well as the lithostratigraphic sequences.Third,carry out surveys along main geological lines in order to establish the stratigraphic framework of the basin.Fourth,carry out geological surveys to complete 1∶50,000 geological mapping.Finally,make an integrated analysis and select important areas and sections to conduct a detailed study and establish a depositional model of the whole basin.