Abstract: In order to meet the requirements of the first harvest of ratoon rice in China, aiming at the problems of lack of row matching function and high rolling rate in the first harvest of ratoon rice in China, a crawler type automatic row matching system of ratoon rice combine harvester was designed with the wade Xuanlong 4 LZ-3. 0 E rice harvester as the carrier and the key technologies in mechanical, hydraulic and electronic control fields. In the wide narrow row planting mode,the system ensures that the crawler of the harvester runs in the middle of the wide row to avoid rolling to the stubble of ratoon rice and affecting the second season yield of ratoon rice. It includes row detection unit and row control unit. The field experiment showed that the automatic control system was installed in the ratoon rice combine harvester. When the forward speed,the power on time of three position four-way valve and the throttle valve opening are set to 0. 556 m/s, 1. 5 s and middle respectively, the effect is the best, and the rolling rate is reduced to 5. 6%-5. 8%.