Fifteen samples have been continuously sampled in the E-W direction of the Yueyang experiment area （35 square kilometers）. These samples were collected from a wide range of different rock patterns such as river-lake sediment（Q）

fragmental rock（K）

sand slate（Pt） and granite. Analysis of optical power spectrum has been applied to obtain the power spectrum curve and power spectrum distribution curve

which is helpful for:1. obtain the strike of reflectance planes which will correspondingly have maximum values of back scatter. These planes are usually terrain slopes fact

outcrop surface

and structural fracture planes.2. The angle included between the direction of the maximum values can well reflect the angle made by the confluencing branchravine.3. calculate the drainage system density.4. analysis the general feature of topography in the sample area. The general feature of topography has close relationship with the characteristic of the lithologic association.We can determine the predominant direction and concentration density of lineament

and discriminate some types of rock in the studied area by spectrum analysis.