Carbonate cements commonly developed in the deep clastic rocks of the Eocene Kongdian Formation in the Jiyang Depression, Bohai Bay Basin. On the basis of general thin sections, scanning electron microscope, X ray diffraction, cathodoluminescence, measurement of fluid inclusions and carbon oxygen isotope results, in this paper, carbonate cements of deep sandstone of the Eocene Kongdian Formation in the Jiyang Depression have been deeply researched. The results showed that: the type of carbonate cements are calcite, iron calcite, ankerite and siderite etc, cementation including early basal cement, diagenetic punctate cementation, fracture filling developing in late stage of diagenesis, cement in vertical and horizontal distribution has certain regularity. Early basal cement formed mainly in chemical sedimentary differentiation in the original water medium, mainly occurred in the contemporaneous lacustrine deposition, caused by the chemical saturation differentiation. Diagenetic carbonate cements is relate to the free flow of fluid, transformation of clay minerals, thermal evolution of organic matter, geological environment change, deep thermal fluid caused by the fault activitiy may also the reason. Carbonate cements has obvious effect on reservoir reconstruction, early basal cement have stong cementation and anti compaction, diagenetic carbonate sedimentation significantly blocked reservoir space， dissolution of carbonate cements during the diagenetic process improved the quality of deep reservoir.