The present invention discloses an area and normal vector-based grid simplification method for unsmooth surfaces. The method comprises the following steps that: all vertices and surfaces in a three-dimensional grid are read, the basic quadratic matrix and initial quadratic error matrix of the vertices and surfaces are calculated; the estimation error of the folding of each side and the positions of new vertices are calculated, after the sides are folded, the cost of the new vertices contains normal vector constraints, minimum folding cost and the positions of a new vertex and an original vertex which are corresponding to the minimum folding cost are stored in vertex attributes, and the folding error is interpolated into a priority queue; sides with the minimum folding cost are extracted from the queue, folding operation is performed on the sides, related vertices and surfaces are updated; and the method dose terminate until a set simplification condition is satisfied. With the method of the invention adopted, the grid can be quickly simplified, and at the same time, the detail features of an original model can be retained as much as possible. As for non-fluid and non-smooth surfaces, the method can better retain detail features and achieve a more outstanding simplification effect compared with a traditional method, and therefore, the method can improve an overall simplificationeffect.