The utility model discloses a non -circular gear mechanism is planted to helical gear alms bowl seedling zigzag width course. At present, capable mechanized the transplantation generally through transplanting mechanism's staggered arrangement with two sets classs of row spacings of rice zigzag width to the slope installation realizes. The utility model discloses well unilateral mechanism just can realize the transplantation of two lines of seedlings, transplants the orbit through the gear train implementation space that has space transmission characteristic, has guaranteed the upright degree of seedling, compound train be two -freedom -degree mechanism, adopts fixed transmission ratio 's knuckle -tooth wheel in the transmission case or adopts the non -circular gear, adopts the gear combination of non -circular gear and crisscross helical gear in the gear box, and two power inputs of central non -circular gear and transmission case make transplants arms and realize that differentials rotate, and differential gearing makes mechanism's freer drive ratio of acquisition on not constant speed transmission characteristic and space transmission characteristic basic to realize big latch closure space " 8 font " the orbit of complicated " directly pressing from both sides the seedling " formula.