The construction of dams alters the hydrodynamics of rivers, consequently leading to a significant influence on the deposition of pollutants within the rivers. To investigate the impact of cascade dam construction on the distribution of heavy metals in river sediments, samples were gathered from the Liujiang River. The analysis included the content of 10 heavy metals (Cd, Cr, Zn, Cu, Hg, Pb, As, Ni, Sb, and Al), as well as pH, particle size, and organic matter content of the sediments. The results showed an overall increasing and then decreasing trend of all heavy metals in the sediments of the Liujiang River from upstream to downstream. The highest concentrations of eight different heavy metals were found downstream of the three terrace dams. The levels of organic matter and ratio of clay particles were closely mirrored the spatial pattern of heavy metal distribution, exhibiting a strong correlation. Studies indicate that sediment heavy metal pollution is mainly affected by runoff contributions. The hydrodynamics are altered by the installation of cascade dams, resulting in the capture of sand particles by the dams and the subsequent downstream accumulation of heavy metals, together with clay particles.