One kind of slurry with low permeability coefficient and certain adsorption and retardation to pollutants in leachat is developed in anti-seepage engineering of leachate for domestic waste landfill site. Through the orthogonal experiment, the selected optimal formula of the slurry with a bentonite base is: bentonite 20%~30%; cement 15%~25%; fly ash 20%~25%; Na2CO3 1.0%~1.4%; diluent FCLS 0.35%~0.75%; and etcaeteras is water. Concretion stone ratio of this slurry is greater than 99.6%; concretion body 28 day permeability coefficient is less than 0.8×10-7cm/s, unconfined compressive strength is less than 2.0MPa; elastic modulus is 50～800MPa. The slurry concretion body’s hindered COD, BOD, NH4-N and phosphorus adsorption rates reach upper 82%, block rate reaches upper 99% to Hg, Pb and other heavy metal ions. The slurry concretion body’s permeability coefficient is low, and its adsorbed or blocked function to landfill site leachate is very well. Meanwhile, it has considered reducing the compressive strength and brittleness of the concretion body, enabling it to have certain plasticity and toughness adapted for the distortion of the base for domestic waste landfill site.