<p>With rapid industrialization and urbanization, the problem of heavy metal pollution has become increasingly severe. Among these, Zn²⁺ pollution causes serious damage to the soil structure and mechanical properties. As a new soil solidification method, urease-induced calcium carbonate precipitation (EICP) can effectively solidify Zn²⁺-contaminated terra rossa. However, the curing effect is limited due to the lack of nucleation sites for CaCO₃ in EICP, to further improve the effect of EICP curing of Zn²⁺-contaminated terra rossa, this study proposed the addition of biochar to Zn²⁺-contaminated terra rossa for improvement. In this study, the effects of different biochar contents and curing agents on the curing effect were analyzed using unconfined compressive strength, toxicity lea, ching, and CaCO₃ product tests, and the curing mechanism was investigated using scanning microscopy. The results showed that EICP combined with biochar can effectively increase the production of CaCO₃, enhance the strength of solidified Zn²⁺-contaminated terra rossa, and reduce the leaching concentration of Zn²⁺. This is mainly because biochar provides nucleation sites for CaCO₃ formation and promotes the mineralization reaction of EICP, thus effectively solidifying Zn²⁺ contaminated terra rossa. The results provide new ideas and a theoretical basis for the engineering practice of EICP combined with biochar to solidify Zn²⁺-contaminated terra rossa.</p>