The vectors, with certain attributes in three-dimensional space, are usually distributed at random and form an ellipsoidal cluster. The extraction of this part of imformation with the conventional method is allways very difficult owing to complex calculation. The three-dimensional vector sifter, which can extract imformation rapidly, is developed in this paper, and an application example is given, which is used in the extraction of the imformation of a gold mineralization- alteration zone in remote-sensing images.