An image acquisition system was designed for fruit machine vision grader to obtain image information about the whole surface of each fruit in fruit flow on the roller conveyor of the grader. The conveyor could transport quasi-spherical fruits with different size and force them rotating with an approximately equal rotational speed on the rollers. With the conveyor and a synchronization control system, a real-time acquisition method of dynamic image sequence of the fruit flow was presented, which could acquire dynamic image sequence of the fruit flow with approximately equal fruit rotation angle between consecutive images. Experimental results show that the image acquisition system can capture 6 sequential images of each fruit in the fruit flow, and fruits regardless of size rotate about 60° between two consecutive images. One complete revolution could be done in 6 sequential images. 