Abstract: For the problem that traditional algorithm of point by point interpolation based on Delaunay triangulation network can not give attention to both interpolating precision and executing efficiency, and according to the geometry characteristics of both Voronoi cells and Delaunay triangles, the paper brings forward the algorithm of point by point interpolation based on local dynamic optimal Delaunay triangulation network. Some experiments that interpolating multibeam survey data into grid digital depth model(Grid DDM), have been done to validate the algorithm’s validity. The experiment results show that the algorithm is characterized by good interpolating precision, meanwhile, the executing efficiency is also improved.