To reveal the correlation between the size, shape and weight of pear fruit and the size, shape of pear leaf, twenty pear fruits as well as their leaves were selected as experimental samples and 8 pear fruits and their leaves as test samples. The images of the experimental fruit and leaf samples were collected and transferred to binary images through cutting process. The numbers of pixels in periphery of the images are representing the perimeter of fruits and leaves and the numbers of pixels within the region are respectively representing the areas of fruits and leaves, combined with the correlation model for perimeter and area in fractal theory, the fitting functions between perimeters and areas for pear fruits which is y=1.034 2x+0.109 8, and for pear leaves which is y=1.480 7x+1.245 5 were obtained. In a similar way, the fitting function between leaves’ perimeters and pears’ perimeters which is y=0.795 5x+0.778 7, between leaves’ areas and pears’ areas which is y=0.526 1x+1.433 1, and between leaves’ areas and pears’ weights which is y=1.930x+2.718 were obtained. The fitting precision of these funActions reached 90% by testing experiments.