Abstract: An algorithm which was used to locate individual mushroom was put forward in this paper. By using the algorithm, it is helpful to complete image processing for mushroom picking robot, and it supplies the theoretic basis for image processing to locate mushrooms in the growing bed. The main contents include the followings: digital characteristics of mushroom image information; algorithm for extracting mushroom contour; discrete Fourier transform to mushroom contour. A new method to calculate mushroom centroid coordinates based on the boundary information was put forward. Fourier descriptors can be used to conduct various operations to mushroom contour, such as translation, rotation, and scale. Besides, Fourier inverse transform allows reconstruction of mushroom contour. Finally, by analyzing mushroom image, the algorithm for locating mushroom and Fourier description to describe mushroom contour are greatly effective.