he authors analyzed chemical characteristics and differences between sedimentary rocks, and the results obtained have established the application basis for X-ray fluorescence (XRF) analysis in logging, which is a new logging technique called XRF-logging. The differences in lithologic characters and thicknesses of strata provide a prerequisite for the stratigraphic analysis with the XRF-Logging technique. It is proposed in this paper that the decimeter should be used as the criterion of the lower sampling limit for the XRF-logging technique. A practical procedure for identifying lithologic character and judging horizons using the XRF-logging technique is illustrated in this paper, and a prediction of the application vista of the XRF-logging technique is also given. It is pointed out that the main element database of sedimentary rocks and stratigraphic profiles should be established for further application of the XRF-logging technique.