A fruit sorting machine that consists of a push-rod mechanism and an image processing system had been developed in this study. The image of fruit was grabbed by a CCD camera while the fruit was rolling due to the push- rod mechanism. The CCD camera could grab two rows-each row contained 3 fruits-that was a total of 6 fruits in one image. The perimeters of two fruits in the front of two rows could be evaluated after completing the image processing of three consecutive images. Two kinds of fruits, apple and orange, were used to test the machine. According to the results, when the speed of the push-rod mechanism was 2.1 cm/sec, the average time spent on calculating fruit perimeter is about 3 sec, and the precision in average is 95.9% and 97.0% for orange.