In this paper, an interference method for pattern recognition is proposed. A test pattern may be compared with a reference pattern by overlapping the two transparent patterns with a lateral displacement in a coherent beam. If the two patterns are sufficiently similar, regular parallel fringes will modulate the common Fraunhofer diffraction pattern of the two samples being compared. The regularity of the interference fringes is a measure of the similarity between the two patterns. The effect of even a small relative rotation，however, will limit severely the region of regularity of fringe patterns.