Abstract: In recent years, there have been many large bank slope collapses in the Shakou dangerous levees of the lower reaches of the Xijiang River, Guangdong Province.After the implementation of the bank collapse reinforcement project, the hidden danger of the dangerous levels has not been effectively alleviated.Based on the underwater topographic data of the Shakou section from 1999 to 2016,the riverbed evolution analysis was carried out, and the flow characteristics of the dangerous levees under typical frequency flood conditions were analyzed by establishing one-dimensional and two-dimensional hydrodynamic mathematical models.The results show that the riverbed of Shakou reach is stable after 2010,but the erosion with the intensity of 0.3～0.5 m depth may occur under the condition of a large flood.The left branch is the main flood discharge channel where the dangerous levees are located, and the nearshore velocity of the dangerous levees is large.The causes and development of the dangerous levees are mainly driven by the river regime and the geological conditions of the embankment base.The self-weight of the soil and the seepage in the slope are the main factors causing typical dangerous levees, and the water flow erosion has a boosting effect.Combined with the results of the field investigation, the idea of combining river regime adjustment with bank slope protection was put forward, which can provide a reference for the follow-up comprehensive improvement of dangerous levees.