Abstract: The paper presents the working process of mushroom pickup robot, the emphasis is put on the discussion of the basic algorithm of image analysis used in its computer vision system. The main contents are the digital characteristics of mushroom and seedbed image information; algorihm used in extracting mushroom edges; the calculations of perimeter, area and central coordinates for an enclosed curve. The algorithm is used as image analysis for information obtained in real working environments, with results fairly consistent with practical objects, thus, showing that the algorithm proposed is feasible.