Carbonate hardgrounds, developed upon oncolitic wackestone and oolitic grainstone in the Cambrian Miaolingian of the southern North China platform, exhibit a sharp truncation of underlying carbonate deposits. This study demonstrates that the presence of radial fibrous calcite cements and microcrystalline cements with a thin isopachous rim, observed between carbonate grains beneath the hardground surfaces, indicates early marine cementation.During 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 wavescour, producing carbonate hardgrounds. Simple, planar hardgrounds represent early cemented surfaces that were subsequently exhumed during a periodof submarine erosion. These surfaces exhibit minimal modification and bioturbation postexposure. In the study area, the hardground interval from the second member of the Mantou Formation (Cambrian Miaolingian) developed within an intertidalsubtidal channel characterized by alternation low and highwater energy. Microcrystalline calcite precipitation was the main cementing agent in this environment. Conversely, another hardground interval, from the Zhangxia Formation (Cambrian Miaolingian), formed during the construction of highenergy oolitic shoals along the platform margins. In this setting, physicochemical precipitation and early seafloor cementation were more active. The occurrence of hardgrounds in the study area provides evidence suggesting that seawater chemistry and benthic ecology were conducive to the early cementation of carbonate sediments during this period. As a prominent manifestation of early seafloor cementation, hardgrounds play a pivotal role in understanding the early diagenesis and lithification characteristics of carbonate sediments. Moreover, their formation process and genesis provide significant insights into shifts in palaeoceanographic conditions and benthic ecosystems.