The utility model discloses a seedling hardening device adopting floating tobacco breeding, including nutrient solution groove, the last cell body that holds the nutrient solution that is equipped with of nutrient solution groove, the port portion of cell body is equipped with the step, the upper end of step is the reference surface, the fixedly connected with of port portion of step is about thesymmetrical vaulting pole in pairs of nutrient solution groove, and nutrient solution groove was kept away from to every vaulting pole one end is all articulated to have a wiring gyro wheel, every nutrient solution groove's the equal fixedly connected with support in one side, every are kept away from to the vaulting pole nutrient solution groove was kept away from to the support one end is all articulated to have a coiling gyro wheel, every the one end of the pivot of coiling gyro wheel runs through support and outside the extension, the outside one end welding of extending of pivot of coiling gyro wheel has the handle, the tip side of coiling gyro wheel is equipped with the jack of a plurality of equipartitions, fixedly connected with sleeve on the support. The utility model discloses compact structure, the practicality is strong, and cost low cost can effectively solve the problem that seedling work load is big of smelting, easily promotes.