The Chenghai fault zone, acting as the eastern boundary fault of the Dali graben system, plays a crucial role in understanding the extrusion processes along the southeastern margin of the Tibetan Plateau. A deeper understanding of its Late Cenozoic activity is essential for interpreting regional tectonic dynamics. Since the Pliocene, the Chenghai fault zone has transitioned to strike- slip motion, but the initiation time of this strike- slip activity and the characteristics of faulting in the southern segment remain controversial. This study employs remote sensing interpretation, field investigations, and structural stress field inversion to delineate the geometric and kinematic characteristics of the Qina- Binchuan segment of the Chenghai fault zone. By integrating previously published chronological data and seismic records, the tectonic evolution of the Chenghai fault zone since the Pliocene is clarified. The results indicate that the southwest segment, particularly the Qing Shui- Zhou Cheng fault, exhibited intense activity prior to the Middle Pleistocene, subsequently experiencing a marked decline in activity during the Late Pleistocene. Conversely, the southeastern Binchuan fault and the Shangcang- Yupeng fault currently demonstrate the highest activity levels, suggesting a shift of fault activity toward the east in the southern section. Analysis of the geometry and kinematics of the Chenghai fault zone reveals that the Chenghai fault zone has undergone rotation since the Pliocene. Based on existing studies, this rotation is interpreted as a response to the clockwise rotation of the southeastern margin. This research provides important data on the migration of fault activity during the evolution of strike- slip fault systems and offers new understanding of the mechanisms by which block rotations help regulate extrusion during the plateau, s material extrusion process.