<p>Magnesium oxide (MgO), as a powdered active substance, can also be used as an activator to prepare binder for the heavy metal contaminated soils treatment. However, for the Cd²⁺ contaminated soils, the cement-based has a poor treatment effect on it. Therefore, the MgO is used as an activator, ground granulated blast furnace slag (GGBS), fly ash (FA) as raw material to prepare Mg-GG-FA binder for Cd²⁺ contaminated soils treatment, and the effects of raw materials mixing ratios and MgO content on the effect of the Mg-GG-FA stabilized Cd²⁺ contaminated soils were investigated. The results show that the compressive strength of Mg-GG-FA stabilized Cd²⁺ contaminated soil increases with an increase in GGBS and MgO content, the Cd²⁺ leaching in stabilized soil was significantly reduced by Mg-GG-FA binder addition, the Cd²⁺ leaching decreases with an increase in GGBS and MgO content. The pH of the Mg-GG-FA stabilized Cd²⁺ contaminated soil increased with the GGBS and MgO content, decreased with the increasing curing age, and the pH ranges from 9.59 to 10.46 at 28 days. The resistivity of stabilized Cd²⁺ contaminated soil increases with an increase in GGBS and MgO content, and has a good correlation with compressive strength. An increase in GGBS and MgO content introduces more Ca²⁺ and Mg²⁺ in the Mg-GG-FA binder, promoting the gels formation, thus improving the solidification/stabilization (S/S) effect on Cd²⁺ contaminated soil.</p>