The shape of wheat kernels is one of the most important criterions for quality inspection and grading. This paper has used Fourier describer to describe the three views of wheat shape accurately and has had a counter-construction operation. Also it verified this method for describing the shape, small but complex. Finally, the appropriate characteristic parameters were selected, and the BP-network was used to classify the four varieties wheat kernels. This method deserves a recognition rate of 98%~99%.