Being aimed at computer imitating of terrain realistic image , we make research on midpoint displacement (MPD) algorithm which is used to generate Fractal Brown Motion and present an algorithm of generation techniques to controlled fractal terrain shape based on meshsizing algorithm of scattered characteristic data points in this paper, through the meshsizing algorithm and meshsizing elevation sampled data , elevation of each gridpoint is calculated. Combination of traditional MPD and gridizing algorithm of the data points can control the terrain rise and fall. By the means of gridizing the data points, it's possible to control the rise and fall with quickness and convenience.