The formation of the Wuhai broad valley (WBV), located at the junction of the Yinchuan basin and the Hetao basin, provides a visual record of the historical evolution at the end of the upper reaches of the Yellow River. However, the stratigraphic- chronological sequence of the Yellow River terraces in this section has not yet been established, and the formation and cutting history of the Yellow River in this area are still unclear. This paper presents a detailed investigation of the WBV, based on field geomorphological, stratigraphic, and sedimentological analyses. Four levels of fluvial terraces were identified on the east side of the WBV, and their ages were determined using optically stimulated luminescence (OSL) dating. Results show that terrace T1 is a depositional terrace with an abandonment age older than 0. 52±0. 04 ka. Terraces T2~T4 are basal terraces, characterized by a similar sedimentary sequence consisting of fluvial deposits in the upper part and lacustrine deposits in the lower part. The maximum estimated abandonment ages for terraces T2, T3 and T4 are about 41. 98±2. 70 ka, 67. 48±4. 07 ka and 102. 32±6. 00 ka, respectively. The average incision rates from T4 to T3, T3 to T2, and T2 to T0 are calculated to be 0. 11 mm/a (102~67 ka), 0. 24 mm/a (67~42 ka) and 0. 26 mm/a (42 ka to modern), respectively. This shows a gradual increase in incision rate since 102 ka. The age of the lacustrine deposits in the terraces T2~T3 coincides with the development of the Late Pleistocene “Megalake Jilantai- Hetao” indicating that the extent of this megalake reached the study area during this period. The formation of the fluvial terraces in the study area was driven by the shrinking and disappearance of the “Megalake Jilantai- Hetao” representing a transition between lake- river landforms at the upper reaches of the Yellow River in the Late Pleistocene. Through detailed comparisons with low- level sequences of various fluvial terraces around the Ordos block, combined with regional tectonic and climatic information, it is concluded that the formation of the Late Pleistocene fluvial terraces in the WBV and the transition between lake- river landforms were mainly controlled by tectonic activities.