To resolve the problems of excess levels of Cu and Mn heavy metals and low pH in the soil of Xiangshan No. 3 pond, a series of sludge solidification samples were prepared using mineral-based composite cementitious materials as binding materials. The effects of curing agent content on the unconfined compressive strength, impermeability, pH, and heavy metal leaching of the sludge solidification samples were studied, and the mechanism of in-situ remediation of contaminated soil was preliminarily discussed. The experimental results showed when the content of curing agent was 7.5wt%, the unconfined compressive strength of sludge solidification sample (28 d) was 1.03 MPa. which gave the sludge soil in No. 3 pond a certain strength, thus enabling the utilization of farmland resources. Meanwhile, the permeability coefficient of the sample was 1.436×10-5 cm/s. The concentrations of Cu and Mn ions in its leachate were 0.058 and 0.021 mg/L, respectively, which were much lower than the standard limit, and the fixation rates were 96.13% and 99.90%, respectively. The increase in pH and the generation of hydration products C-S-H and AFt can effectively improve the stability of Cu and Mn ions in soil.