Basin-scale underground-water-to-surface-water nitrogen transportation blockage preferential control region division method

The invention provides a basin-scale underground-water-to-surface-water nitrogen transportation blockage preferential control region division method. The method comprises the steps: determining a preferential control region recognition target region in a research region according to an interaction relation of underground water and surface water; in the preferential control region recognition target region, dividing the grade of underground water nitrogen pollution to form an underground water nitrogen pollution grade division map, and performing underground water nitrogen pollution special vulnerability estimation and grade division to form an underground water nitrogen pollution special vulnerability grade division map; based on a GIS technique, performing map layer overlapping on the underground water nitrogen pollution grade division map and the underground water nitrogen pollution special vulnerability grade division map; further dividing the grade of an underground-water-to-surface-water nitrogen transpo