Based on a mixed network of RS485-bus and CAN-bus, a distributed synchronization control system for fruit machine vision grader was designed by adopting a modular structure. The control system could realize synchronization with a timing signal generated by a rotary encoder, could trigger cameras timely to capture dynamic image sequence of fruits flow on conveyor of the grader when they were in preconcerted positions of the grader, could register dynamically the fruits grade information with their real-time positions after their grades had been determined by image processing unit of the grader, and could instruct corresponding discharging actuators to implement discharging process of the fruits when they had been conveyed to the discharging ports of their grades. The experimental results show that different parts of the grader are coordinated with each other under control of the synchronization control system and all fruits have been discharged at the prospective discharging ports.