In recent years,It is all along argued that whatever sedimentary and tectonic setting in northern margin of Yangtze Block is during the Ordovician-Silurian Period.Method:Systematically sampling sandstones and mudstones of Wufeng Formation and Longmaxi Formation and analyzing their major and minor elements,their provenance and tectonic setting are discussed from the perspective of their geochemical features in this paper.Conclusions:Major element SiO2 contents of sandstones and mudstones range from 39.57% to 87.16%, and mostly are higher than North America Average Shale’Content(NASC),while Al2O3 contents change from 3.41% to 14.98% and are all lower than those of NASC.NASC normalized major elements spider diagram show that these contents such as MgO,CaO,MnO2 and P2O5 are clearly lower than NASCs’. Compared to major elements of contemporary mudstones from Changning-Shuanghe region located in southern margin of Sichuan basin,these sandstones and mudstones in northern margin of Yangtze block are charactered by higher SiO2and lower MgO、CaO contents,which indicates that material components of the latter are mainly dominated in terrigenous clast.Relative to minor elements of NASC,some elements such as Sc,Sr,Co,Zr,Hf are relative depleted,some V,U,Sb,Ba are relative enriched, the other Cr、Ni、Nb、Ta have approximate contents.The ratios of LREE/HREE and (La/Yb)N show that sandstones and mudstones of Wufeng Formation and Longmaxi Formation might have a feature with LREE depletion and HREE enrichment. NASC-normalized trace element pattern of sandstones and mudstones in this study are entirely featured by slight right-tilted ones with bulkδCe negative abnormalies,δEu positive abnormalies of Kuanyinchiao Member and Longmaxi Formation indicate some hydrothermal activities of oceanic floor during that time.Provenance and tectonic setting diagram of these sandstones and mudstones display their source rock of provenance have multiple kinds of material components,which principally inherited from felsic rocks and mixed with granitic and andesitic rocks.Tectonic setting during source rocks formation is mostly located in passive continental margin and partly in active continental margin and continental island arc,which is coincident with regional geological background of passive continental margin in northern margin of Yangtze block during the late proterzoic-early palezoic period.