The Datong basin is a Cenozoic rift located in the central part of North China Craton. It has experienced intensive and persistent rifting since late Miocene. Based on the analysis on the kinematics and dynamics of the marginal faults, the summary on the Cenozoic sedimentary and basaltic strata and the discussion on regional dynamic background, writers proposed the formation mechanism of the Datong basin. Since 10~8 Ma, the NW extending tectonic stress field formed on the northeastern margin of the Ordos block and acted on the marginal faults resulting in the Datong basin’s forming. The formation of the Datong basin corresponds to the lithosphere thinning process and may be related to the far field effect of India—Eurasia collision and Pacific—Eurasia collision. What’s more, the article shows some new facts. The normal fault stress field of the Datong basin is that σ1 is vertical, σ2 and σ3 is horizontal, the strike of σ3 is about 150°, which differs from the strike slip fault stress field of North China. The K Ar age of Dayukou basalt in Datong volcanic field related to mantle activity is 0.68±0.13Ma. The Datong basin has characteristics of intraplate narrow rifts. All these research provide a new basis for building the Cenozoic kinematics and dynamatics model of the Shanxi Rift system.