Drawing countersigning means that all professional designers sign on the drawing countersigning column. Specifically, for example, after the construction drawing of architecture major is completed, it will be sent to the majors of structure, water supply and drainage, electricity, heating and ventilation for review. After confirming that there is no conflict between the majors, the designers of each major will sign the countersign column, and so on, and the drawings of other majors will follow the same process. Drawing countersigning is a technical measure to ensure design quality.