In spite of the well-established design and construction approaches of slag-cement-bentonite slurry walls, the materials deteriorate inevitably in contaminated land. The development of ef-fective materials which are sustainable, resilient and self-healing over the lifetime of slurry walls becomes essential. This study, for the first time, adopts styrene-ethylene-butylene-styrene (SEBS) polymer to modify slag-cement-bentonite materials to enhance mechanical and self-healing per-formance. The results show that the increase in SEBS dosage results in significantly increased strain at failure, indicating the enhanced ductility thanks to the modification by the deformable polymer. The increased ductility is beneficial as the slurry wall could deform to a greater extent without cracks. After the permeation of liquid paraffin, the SEBS exposed on the crack surface swells and seals the crack, with the post-healing permeability only slightly higher than the un-damaged values, which exhibits good self-healing performance. Scanning electron microscopy and micro-computed tomography analyses innovatively reveal the good bonding and homoge-neous distribution of SEBS in slag-cement-bentonite. SEBS acts as an binder to protect the slag-cement-bentonite sample from disintegration, and the swollen SEBS particles effectively seal and heal the cracks. These results demonstrate the SEBS modified slag-cement-bentonite could provide slurry walls with resilient mechanical properties and enhanced self-healing performance.