Innovation of the separating-planting mechanism is one of key technologies to innovate rice transplanter. Firstly, structure and work principles of a new type of the separating-planting mechanism with differential elliptic gear system of high-performance rice transplanter are introduced in this paper. Its kinematics models were established on the basis of the transmission analysis of differential elliptic gear system. According to the different agronomic requirements of South China and North China, CAD/CAE technology is applied to find out two sets of proper structural parameters easily. And its kinematic performances are compared with the separating-planting mechanism of high-performance rice transplanter made in Japan. Finally, the test shows that the separating-planting mechanism with differential elliptic gear system can work smoothly. Its scheme design is reasonable and practical, and the theoretical annalyses are in good agreement with the experiemental results.