Abstract: For the problem of heavy metal pollution in groundwater, the current remediation materials have poor mobility, and it is difficult to form effective reaction zones after injection. Active silica-aluminum materials can not only fix heavy metals, but also migrate effectively in aquifers. In order to construct reaction zone in situ, an active silica-aluminum material was developed in the laboratory by means of physicochemical characterization, isothermal adsorption experiment, stability test, column simulation experiment, etc. In addition, site-scale pilot test and engineering demonstration were carried out in the historical leakage area of groundwater contaminated by Zn and Ni at downstream of the tailings pond of a non-ferrous metal mining area. The results showed: (1) The active silica-aluminum had nanoscale pore size and amorphous morphology, and the surface zero charge point was about 1.7; the maximum adsorption capacities for Zn and Ni were 94.41 mg/g and 2.40 mg/g respectively, the fixation mechanism included ion exchange, precipitation and so on, and the medium of natural sand did not affect its fixation effect on heavy metals; the stability of active silica-aluminum was very well, the polymerization reaction increased with the decrease of pH and the extension of time, and active silica-aluminum followed the liquid-solid two phases migration mechanism. (2) After injected in the simulated sand column, the concentrations of Zn and Ni at the sprue reduced to undetected rapidly, and the treatment capacity of heavy metals at the exit continued to increase. The permeability coefficient of the simulated sand column first decreased and then increased, with little overall change. (3) In-situ reaction zone was constructed by injecting active silica-aluminum to immobilize heavy metals in groundwater of the site. The concentrations of Zn and Ni in the pilot area decreased by more than 80% within 40 d. In engineering demonstration area, the migration and diffusion of active silica-aluminum was obvious and immobilization effect was remarkable, Zn concentration decreased by more than 92.3%, after 5 months of monitoring, the Zn concentration remained below the standard value of groundwater III. Injecting active silica-aluminum can effectively construct in-situ reaction zone to remediate groundwater contaminated by heavy metals.