In the process of building construction, concrete crack is one of the more common problems. All kinds of small cracks in the concrete floor slab are unavoidable and the impact caused by these cracks is limited. However, some large and deep cracks will affect the overall quality of the building, but also bury some safety risks. Therefore, in the actual process of civil engineering construction, it is necessary to make a reasonable analysis of the causes of the formation of cracks, and develop targeted measures to improve each link. This reduces the chance of cracks and ensures the safety of the building.