The soft foundation has a great influence on the stability of embankment.The law of influence of different replacement depth and toe external width on the deformation and stability of the dyke is researched by numerical analysis.The results show that new levee foundation ground surface settlement decreases and the safety factor increases with the increase of the thickness of the filling replacement.When the replacement thickness is certain,the influence is not obvious by increasing replacement width of dike toe external field,but there is a significant influence on the stability.The reinforced zone width of foundation should increase with replacement depth decrease.The results have certain significance to guide the design of soft base replacement.