Abstract: To enhance the productivity of semi-automatic grafting machines, a automatic grafting method with flow line was proposed. Based on the characters of multi-position, a rootstock cutting mechanism was designed to cut rootstock in transverse and longitudinal section. The results showed that With 4 mm of the diameter of rootstocks, the elongation of holding belt was 200% and the included angle of aligning faces for holding rootstock was 90°, the successful ratio for holding rootstock was 95%. With 1.8 mm of the blade thickness, the residence time for cutting in longitudinal section was equal or greater than 0.8 s, the incision width of rootstock cut by the blade was the maximum. A leading unit was installed to the lead scions deflected at the inserting position to guarantee inserting a scion into a incision of rootstock cut by the rootstock cutting mechanism. The research indicated that compared with the manual operation, the rootstock cutting mechanism exhibits the advantage of the fast cutting speed and fine operating stability.