Since the application of prototype test of the Sanmenxia Reservoir in 2002, the lower reaches of the Weihe river washed silt appears "overall from Deposition change into scour" significant change, before and after of the implementation of comprehensive engineering governance of the lower of Weihe River, the distribution of scour and silting was "upper and lower part is scour, central section is siltation, overall is still scour ".The analysis showed thatbefore the comprehensive improvement，descending Tongguan elevation is the main impact factor of Weihe River downstream scouring, during the comprehensive improvement the increase of erosion in the lower Weihe River is mainly caused by human activities such as the large scale construction of soil digging in the river course. It is suggested that the river control project should be constructed in a timely manner in the adverse deformed river bend to reinforce or renew the flood top-flushing project, strengthen the control over unfavorable river regime, to ensure the safety of the stability of slope and flood control engineering.