This paper introduced mode of collecting、technology of filtering and measuring process about image of three dimension composite preform surface. After image of preform surface which was filtered by based direction adaptive filter(BDAF)

we can calculate spectrun of image of preform surface that had been manipulated. We can measure average angle using method of texture analysis. It has been proved to be correct by sandard image. The experiment shows the system will be accurate. Practice shows that it is one of the effective and new technique about measuring average angle of three dimension composite preform.