Aiming at the shortcomings of existing cut-off walls with polymer during construction, including limited trench capacity, difficult verticality, poor continuity and compactness, the improvement for the construction equipment and technology was carried out and the effects were inspected. The results show that the application of the electronic level instrument of biaxial measuring column realizes the accurate hole sleeve of the cone head plate. Lengthening the guide rod and changing the fixed cone head into one-time movable cone head can improve the speed and accuracy of hole insertion and can ensure the verticality and continuity of the overlapping hole. The integrated construction technology of lifting and injection can avoid collapse or shrinkage of the slot hole, and the uniformity, continuity and compactness of the wall can be ensured. The improvement of the construction equipment and the technology of super-thin cut-off walls with polymer can ensure the verticality and lap integrity of the wall, improve the working efficiency of the equipment, accelerate the construction progress.