Abstract: The rootstock seedlings of nightshade vegetables are offset from the center of the plug tray due to planting deviation and growth difference, which may cause damage to the rootstock seedlings during automatic grafting operations. Aiming at the problem that the position deviation of rootstock seedlings will cause damage to the grafted seedlings, this paper designs a position correction mechanism for rootstock seedlings, which constrains the rootstock in all directions through a pair of seedling holding hands and a rootstock pusher, so as to rectify the position of the rootstock. In order to investigate the damage to the grafted seedlings caused by the position correction mechanism of rootstocks, a damage test of the grafted seedlings caused by the positional correction of rootstocks was designed. The test results show that the deviation correction mechanism can realize the deviation correction of the rootstock seedlings offset from the center point of the plug tray within 4 mm; when the rootstock seedlings are displaced forward, the damage rate of the grafted seedlings with the rootstock seedling position deviation correction mechanism “hulling” back to the offset is 4.9%; when the rootstock seedlings shifted backwards, the rootstock seedling position correction mechanism “pushed” the grafted seedlings with a damage rate of 12.3%. damage; when the buffer material of the seedling hand and the stock pusher was buffered with 0.3mm plastic film, the damage rate of the grafted seedling was 4.9%; when the seedling hand and the stock pusher had no buffer material, the damage rate of the grafted seedling was 6.17%.