Abstract: Using the image of 2R-G-B, Ostu algorithm was used to segment the images of mature oranges and background. Morphologic operation was used to remove the random noise and the object regions were labeled. According to the areas of the labeled regions and their ratios of the least rectangles' length and width, the remnant backgrounds were eliminated. For the overlapped fruits, a new image generated through formula T=Sqrt(S×I) and the boundary of the new image was extracted, with the additional morphologic operation, the overlapped fruits were separated. Finally, the optimized Circular Hough transform algorithm was used to extract centroid coordinates and radius, and then the fruit shape was recovered. The result shows that the correct recognition rate is up to 95%.