Here we present the geological characters, iron isotope and rare earth element geochemistry of iron-bearing chert and carbonate mud mound in the Sailinhudong Group in Inner Mongolia, China. The iron-bearing chert contains elongate highly ramified Fe oxides aggregates, which is similar to submarine hydrothermal Fe-Si deposits. δ56Fe values for iron-rich chert are -0.71‰~-0.25‰, similar to those for submarine hydrothermal fluids. The PAAS-normalized REE pattern shows positive Eu, La and Y anomalies, the characters of the mixture of seawater and high-temperature hydrothermal fluids. These indicate that the iron-bearing chert deposited from submarine hydrothermal activity. The carbonate mud mound (the micrite mound) in the Sailinhudong Group has Fe isotope compositions that isotopically lighter than the normal sedimentary carbonates in the same Group, but similar to those for submarine hydrothermal fluids. It has PAAS-normalized REE pattern that similar to that for chert mentioned above and the submarine hydrothermal fluids. These indicate that the carbonate mud mound also formed related to submarine hydrothermal activity. The existence of iron-bearing chert and carbonate mud mound is accordant with the existence of seismite and earthquake slump-fold blocks reported previously, implying that the Sailinhudong Group deposited in an extending basin when the submarine hydrothermal activities were active. These submarine hydrothermal activities recorded in the Sailinhudong Group may correlate with the extending tectonic setting during 1.3~1.4Ga in the North China Craton.