Following the Lüliang Movement, the Ordos Basin entered a rifting evolution stage, forming multiple deep rift systems from south to north. Currently, the deep Mesoproterozoic strata hold significant hydrocarbon potential, exploration in the deep Ordos Basin remains at a relatively early stage, and the precision of seismic data is insufficient. This has resulted in numerous gaps in the understanding of the structure and evolutionary characteristics of the deep rift systems during this period. This study focuses on the Mesoproterozoic Longdong Rift System in the Ordos Basin. By integrating seismic data and drilling data, it systematically reveals the episodic characteristics, structural-evolutionary features, and genetic mechanisms of the Mesoproterozoic rift system in the Ordos Basin.?The key findings are as follows: ①The Mesoproterozoic of the Ordos Basin experienced multiple tectonic events, with eight unconformities identified and seven structural-stratigraphic sequences delineated. From bottom to top, these are sequences Pt?Ch_Ⅰ~Pt?Ch_Ⅳ (Early Synrift Stage), sequence Pt?Ch_Ⅴ (Late Synrift Stage), sequence Pt?Ch_Ⅵ (Postrift Stage), and sequence Pt?Jx (Epicontinental Sea Stage), reflecting the rift's evolution from a continental fault depression to a marine depression. ②The Longdong Rift System exhibits a half-graben structure, bounded by a master fault on its southern side. The internal strata wedge out northward and progressively deepen southward. ③The rift's tectonic-sedimentary evolution comprises four stages: Early Synrift, Late Synrift, Postrift, and Epicontinental Sea. The rift is characterized as an intracontinental rift driven by subduction along the southern margin of the North China Craton and mantle plume upwelling.?Initially, it functioned as an inland branch of the Xiong'er triple-junction rift system, with extension intensity decreasing northward. The rift activity progressed through initial faulting, volcanic eruptions, sustained extension, and eventual subsidence and demise.