Abstract: Abstract: Compared with other methods of cultivating corn seedlings, seedlings growing in paper tube have the advantage of high efficiency in transplanting. To solve the problems of labor intensity, low efficiency and high cost of conventional transplanting, a transplanter for corn seedlings growing in paper tube was designed in the paper. The critical part of the transplanter is the transplanting disc, which affects the operation performance of the whole machine. To determine the structural and working parameters of the transplanting disc, the physical parameters of paper tube seedlings were measured, the motion process and velocities of paper tube seedlings in the transplanting disc were analyzed. The trajectory equation of paper tube seedlings was designed, and the effects of the structural and working parameters on the motion trajectory of paper tube seedlings were simulated using MATLAB. The optimal parameters were determined, i.e., the rotary speed of the transplanting disc (w) is 7 rad/s, the distance between the center of seedling tube and transplanting disc (L) is 275 mm and the angle that the seedling tube rotating with the transplanting disc (α) is 80°. Field experiments were conducted in a research field at Gu'an county, Hebei province. The working speed of the transplanter was maintained at 5 km/h and the theoretical seedling spacing was set as 200 mm. The experiments were repeated three times. 100 seedlings in the middle of 200 seedlings which were transplanted one time were taken as samples. The upright degree, seedling depth and seedling spacing were measured and their qualified indices were calculated to evaluate the working performance of the transplanter. The results showed that the percentage of upright seedlings is 91%, the qualified index of seedling spacing is 92.6%, and the qualified index of transplanting depth is 79.3%. All the indices are better than standard values and the performance of the new transplanter is better than that of conventional transplanting machines. The coefficient of variation of transplanting depth is 7.4%, which means the transplanter has good uniformity of transplanting depth. The percentage of upright seedlings indicates that the theoretical analysis method for determining the structural and working parameters of the transplanting disc used in this research is feasible. The transplanting depth of seedlings was influenced by soil condition. To obtain desired transplanting depth, the depth of loose soil layer must be deeper than the transplanting depth when preparing field. Although the qualified index of seedling spacing is more than 90%, the coefficient of variation of seedling spacing is as high as 21%. The main reason is that the distances between seedlings were changed in seedling delivery system before them coming into the transplanting disc. So the seedling delivery system should be optimized in further study. The data revealed that the transplanter for paper tube corn seedlings performed well in actual operation and the transplanting efficiency can meet the needs of Chinese peasants properly. The new design and the theoretical analysis method in this research can provide a reference for design and application of transplanters.