The carbonate hardgrounds developed on oncolitic wackestone and oolitic grainstone in the Cambrian Miaolingian Series in the southern of North China Platform, which sharply truncate the underlying carbonate deposits. In this study, the radial ?brous calcite cements and microcrystalline cements with a thin isopachous rim between the carbonate grains below the hardground surfaces indicate that the cements formed by early marine cementation. In the Cambrian, the early cementation zone was sufficiently close to the sediment-water interface to be susceptible to erosional reworking caused by tidal currents and wave scour，producing carbonate hardgrounds. Simple, planar hardgrounds represent early cemented surfaces which are exhumed during a period of submarine erosion that underwent little modi?cation and bioturbation after exposure. In the study area, the hardground interval from the second member of the Mantou Formation(Cambrian Miaolingian Series) was formed in the intertidal-subtidal channel with the alternation of low to high water energy, inferring that microcrystalline calcite precipitation was the main cementing agent; another hardground interval from the Zhangxia Formation(Cambrian Miaolingian Series) was formed during the high construction oolitic shoals of the platform margins, when the physicochemical precipitation and early seafloor cementation were more active. The occurrence of hardgrounds in the study area suggests that seawater chemistry conditions and benthic ecology were suitable for early cementation of carbonate sediments during this period. As outstanding evidence of early seafloor cementation, hardgrounds are of great significance to the study of early diagenesis and lithi?cation characteristics of carbonate sediments, and their formation process and genesis also provide a major basis for changes in palaeoceanographic conditions and benthic ecosystems.