In order to discuss the feasibility of longitudinal seedling feeding mechanism for rice pot seedling transplanting with ratchet gear, the working principle of longitudinal seedling feeding mechanism and the transmission characteristics of ratchet gear mechanism were analyzed. Considering that the pot seedling feeding mechanism of high-speed rotary pot seedling transplanting machine must meet the requirements of steady transmission, accurate transmission ratio, good working reliability, no accumulated error in operation as well as low vibration and noise, the longitudinal seedling feeding mechanism for rice pot seedling transplanting with ratchet gear was designed. The mathematical models of some important geometrical parameters in the design of structure were built and then these parameters were optimized. Besides, the virtual model was also built by using CAD/CAE software. At last, the bench test was carried out. The test result showed that the proposed longitudinal seedling feeding mechanism could meet the working demands of highspeed rotary pot seedling transplanting machine, which provides theory and implement basis for developing this kind of transplanting mechanism.