The invention provides a method for representing navigation grid map for 3D scene, comprising the following steps: extracting the walking hierarchy planes in a 3D scene; obtaining a set of the walking hierarchy planes; removing the isolated planes and the non-walking planes; abstracting the initial non-passable regions of a way-finding role in the walking hierarchy planes so as to abstracting the models in the 3D scene as non-passable regions; conducting region combination to the polygons in the initial non-passable regions so as to obtain a final non-passable region; combining the intersecting regions in the initial non-passable regions to form a final non-passable region; performing constrained Delaunay triangulation to the constraints of the hierarchy planes to form a triangular set; and structuring a final navigation grid by the triangular sets of all walking hierarchy planes. The final navigation grid capable of fully separating obstacles from walking regions. The invention is applied to the technical field of a digital media and can effectively ensure that obstacles are separated from walking regions.