Abstract: In this paper, a kind of separating-planting mechanism of high-performance rice transplanter, separating-planting mechanism with double control unit was introduced, in order to achieve the movement trace of transplanting arm, connected rod mechanism and planetary rod mechanism were used. On the basis of the founding of kinematics model, the software for optimizing structure parameters was programmed by means of Visual Basic in order to find out a set of proper parameters easily. According to the different agronomic requirements of South China and North China, the separating-planting mechanism was developed and optimized, the test results were quite close to the theoretical results.