The strategic importance of key metals, such as lithium, and their implications for national security are gaining prominence in the contemporary geopolitical landscape. The North China Craton, with its abundant lithium- rich clay rock resources, represents a significant exploration target for sedimentary lithium deposits in China. This article focuses on the clay rocks in coal- bearing strata in the southern Shanxi area of the North China Craton. A comprehensive suite of characterization techniques, including X- ray powder diffraction (XRD), X- ray fluorescence spectroscopy (XRF), inductively coupled plasma- mass spectrometry (ICP- MS), Fourier transform infrared spectroscopy (FTIR), and magic angle spinning nuclear magnetic resonance spectroscopy (MAS NMR), was employed to investigate the lithium distribution and sedimentary environment of Benxi Formation clay rocks. These techniques are complemented by chemical phase analysis and clay mineral flotation experiments. Results demonstrate that clay minerals are the main carriers of lithium, including Li- chlorite, illite, and kaolinite. A strong positive correlation exists between lithium content and Li- chlorite content, while weaker positive correlations are observed with illite and kaolinite content. Lithium in samples mainly exists in the octahedral lattice of interlayer hydroxide sheets in Li- chlorite, with lesser amounts occurring in illite and kaolinite. Paleoenvironmental indicators, including salinity proxies \[m(100×(MgO/Al2O3)) and 1000×Rb/K2O values\] and redox proxies \[V/(V+Ni) and Th/U values\], suggest that the lithium- rich clay rocks formed in a freshwater to brackish water environment, characterized by anoxic and oxygen- poor conditions. Geochemical proxies, including Sr/Cu, C ((V+Cr+Mn+Fe+Co+Ni)/ (Na+Mg+K+Ca+Sr+Ba)), and CIA values, indicate a hot and humid paleoclimate during their formation. This study contributes to a better understanding of the formation processes of sedimentary lithium deposits and provides valuable insights for developing efficient separation and extraction techniques of this type of lithium resource.