Dredged silt has the characteristics of high moisture content, difficult consolidation and large volume, and polluted by heavy metals, leading to slow drying, hard utilization and soil hardening, which is unbeneficial of plant growing. To solve the above problems, dredged silt polluted by copper, lead, and cadmium was taken as a study object, which was mixed with fiber, lime, fly ash, kaolin, sodium silicate, sodium carbonate, ferric sulfate and magnesium sulfate. Then polluted silt stabilization and planting tests were performed. The results show that the permeability coefficients after soil solidification are increased by 2 or 3 orders of magnitude. Eight leaching amounts of heavy metals are obviously decreased, which can meet the national standards. The kale grown in solidified silt has faster growing rate with healthier leaf appearance. The optimum proportion of planting is 10% mixtures of fly ash, lime, kaolin, and fiber combined with 6% mixtures of sodium carbonate and ferric sulfate. Using the optimum scheme, the kale has lower heavy metal contents with higher reduction rate of heavy metal leaching amounts compared with other four groups, which can absorb more nitrogen and phosphorus.