In order to ensure the security utilization of heavy metal wastes used in cement-based materials, the solidification effects of cement and the influence of adding bentonite on Pb(II), Zn(II), Cd(II) and Cr(VI) concentrations in the leachate under different pH conditions were investigated. The results showed that, solidification effects of cement on Pb(II), Zn(II) and Cd(II) were better than on Cr(VI). When heavy metal content reached 5 ‰, pH value was kept at 3, the leaching toxicity was still lower than the national standard. After adding the bentonite, the concentrations of heavy metals in the leachate can be further reduced. When the mixing amount of bentonite was 30% and under acid condition, the concentrations of Zn(II), Cd(II) and Cr(VI) in the hardened cement pastes which have been cured for 28 days were reduced by 60.9%, 51.3% and 53.3%, respectively. CH peak value decreased significantly but AFt increased significantly. However, bentonite had the opposite effects on Pb(II). The concentrations of heavy metals in acid solution were higher than the neutral solution.