Electroplating sludge (ES) is a hazardous waste containing various heavy metals. This study aims to evaluate the solidification effectiveness of a geopolymer material prepared from lead-zinc smelting slag (LZSS) on electroplating sludge and elucidate the impact mechanism of organic polymers on this process. The results demonstrate that under the conditions of 3. 5% (mass fraction) alkali content, a water glass modulus of 1. 4, and a liquid-to-solid ratio of 0. 22, the lead-zinc smelting slag-based geopolymer material can safely immobilize 2. 5% (mass fraction) electroplating sludge. The addition of organic polymers enhances the immobilization amount of composite geopolymer material twofold and increases the compressive strength by 27. 45% . At this stage, the total leaching concentration of Cr decreases from 20. 05 mg / L to 13. 65 mg / L, which is lower than the limit specified in the Identification Standards for Hazardous Wastes-Identification for Extraction Toxicity ( GB 5085. 3—2007 ). Mineral composition analysis, microstructure observation, chemical bond analysis, and oxidation state characterization of the solidified matrix indicate that the combined effect of Fe(II) in the lead- zinc smelting slag and organic polymers effectively reduces the toxicity of Cr and enhances the fixation rate of heavy metal ions. This study provides a new approach to the safe disposal and comprehensive utilization of electroplating sludge and lead-zinc smelting slag.