Characterized by strong erosion of the south river bank from the Jingguang railway bridge in Zhengzhou to Dongbatou in Lankao, the lower reach of the Yellow River, which is a hanging river in this part, runs along Jiyuan—Kaifeng rift, with Taikang uplift on the southern side. With the discovery of Zhengzhou—Lankao regional concealed fault between Jiyuan—Kaifeng rift and Taikang uplift based on the interpretation of remote sensing and geophysical exploration information, the following phenomena can be explained reasonably: How does the river come into being, develop and evolve?  What causes the river to stretch straightly from Zhengzhou to Lankao in the EW direction in spite of the fact that the river bed shifts in the river channel?  Why does the river erode the south bank most strongly? The discovery of the fault and the river erosion characteristics is of great significance in river improvement and flood prevention in the lower reach of the Yellow River.