Expansion of city makes some new projects have to be built on earlier landfill.When its foundation is constructed,the current leakproof system must be damaged and the leachate which is full of impure irons will pollute underground water.Moreover,leachate would also erode concrete pile foundation after the piles are finished.To evaluate and decrease the negative influence of leachate,certain piles which are constructed on landfill are studied.By theory research and model calculation,this paper analyzes the process of pollutants transmission and the durability of piles,then draws the conclusion about the relationship of slurry density,thickness of mudcake,infiltration time and slurry loss of single pile;the relationship of newly increased pollution and slurry loss,slurry parameter;the influence of concrete protective cover and derust on pile durability.