The curing agent was used to solidify the sludge contaminated by heavy metal Cu²⁺ and Cd²⁺, and its permeability property was studied. The testing results show that the amount of heavy metal in exudation fluid decreases with the increase of curing time under penetrant with the same pH value. The exudation of Cu²⁺ in acidic conditions is greater than that of neutral conditions under the same curing age. Based on the process of C-S-H gelation, Cd(HCO₃)₂ which is difficultly dissolved in acidic fluid is produced by Cd²⁺ and HCO₃^-, which leads to the few exudation amount of Cd²⁺. The effects of different amounts of heavy metals on the permeability coefficient k and the total exudation quantity of contaminants were investigated, which illustrates that the k and the total exudation concentration are positively related to the increased amount of pollutants when the mass fraction of Cu²⁺ is equal or less than 0.75% and the mass fraction of Cd²⁺ is equal or less than 0.225%. However, the k decreases with the increase of pollutant content when the mass fraction of Cu²⁺ is more than 0.75% and the mass fraction of Cd²⁺ is more than 0.225%. Besides, a scanning electron microscopy was used to analyze the effect of different pollutant concentration on the microstructure of the sample. With the increase of heavy metal concentration, on the structure surface form honeycomb heavy metal hydration products.