Abstract: To develop a satisfying plantlet-cutting mechanism of grafting machine, the authors designed a half-rotating cutting mechanism, optimized structural parameters and developed a simulation cutting test device，then made a cutting test by using five kinds of seedlings including peach, plum, orange, grape and chestnut based on the test device. The results testified the feasibility of the cutting mechanism and showed the sequences of test factors according to the influence on cutting resistance and cutting-out rate. The correlation between cutting resistance and the three factors including seedling average diameter, rotation speed and slide cutting angle, and also the correlation between cutting-out rate and the same three factors were discovered. In conclusion, the half-rotating cutting mechanism is feasible. The three factors including seedling average diameter, rotation speed and slide cutting angle make great influences on cutting resistance and cutting-out rate respectively. It is necessary to make seedlings nursery plants to provide the well-proportioned diameter seedlings, and the rotation speed limit is 50～60 r/min and slide cutting angle is adjusted to a little above 30° .