The invention discloses a method for preventing latticed column groups of wide special-shaped foundation pits from being impacted and causing instability of supporting systems. In the excavation process of the wide foundation pits, a reflection strip adheres to each steel latticed column connection plate 5 in the circumferential direction for realizing the warning effect; when the wide foundation pits are excavated to 1/2H depth of latticed columns, angle iron trays are welded to the steel latticed column connection steel plates distributed in a triangle mode, the lower edges of the angle iron trays are flush with the lower edges of the steel latticed column connection steel plates, peripheral welding is carried out on the angle iron trays and the steel latticed column connection steel plates, and the angle iron trays support H-shaped steel; after the angle iron trays are welded firmly, H-shaped steel 2 with the same length is erected according to the length between adjacent steel latticed column angle iron and the angle iron trays and is erected on the angle iron trays, bottom flange plates of the H-shaped steel and the angle iron trays are welded fully and firmly, web plates and top flange plates of the H-shaped steel and the steel latticed column connection steel plates are welded fully and firmly, and anti-collision H-shaped steel is sequentially constructed between adjacent steel latticed columns according to the method.