Abstract: A CAN-based distributed control system was developed to improve the reliability of automatic guidance for rice transplanter. This system included a master node and three slave nodes. The master node, which used AT91SAM9261 embedded CPU, utilized RTK GPS data and compass data to generate appropriate control commands. By adopting C8051F040 as the key control chip, three slave nodes realized steering control, speed control and transplanting instrument lever control, respectively. A communication protocol was presented for the distributed control network. Road tracking test and paddy field test were carried out based on SPU-68 rice transplanter. Testing results demonstrated that the system was able to transfer and receive real-time messages reliably. And the transplanter could complete all the field operations, such as tracking trajectory, automatic steering, speed changing and transplanting, etc. Road and paddy field testing results also showed that the line trajectory track errors were less than 0.05 m and 0.2 m, respectively, which basically met the requirements of rice transplanting.