Abstract: Large areas of sand bodies are distributed in the coarse facies of the first member of Shanxi Formation (Member Shan1) and eighth member of Lower Shihezi Formation (Member He 8) in the Permian in Ordos Basin. A deposition mode of flood-induced braided river delta from Member Shan1 to Member He 8 is proposed based on paleo-geographic analysis and extensive core observations. The proposed depositional mode is verified via a tank simulation experiment. Results show that broad flat landform, lake-level fluctuations, strong hydrodynamic force, and sufficient sediment supply are the main factors responsible for the large-area distribution of the sand bodies. Under arid climatic conditions, successive transportation by multi-stage flood enables the long-distance expansion of coarse sandstone toward the belly of the lake basin, resulting in the formation of large-area braided river-delta sand bodies characterized by wide distribution and vertical overlap.