The invention discloses a tobacco seedling under-film transplanting machine which comprises a rack system, a power transmission system, a ditch-trenching or hole-digging system, a pesticide delivering system, a transplanting system, a watering system, a herbicide spraying system and a film laminating system. Power is transmitted to a dibber, a pesticide storage box and a transplanting disc through the power transmission system and then the six working procedures of ditch trenching or hole digging, pesticide delivering, tobacco seedling transplanting, tobacco watering, herbicide spraying, and film laminating are achieved in sequence, so that working intensity can be reduced greatly and production efficiency of tobacco seedling under-film transplanting can be improved. The tobacco seedling under-film transplanting machine solves the difficult problem that tobacco seedling under-film transplanting cannot achieve mechanization, can liberate working force greatly, reduces working intensity and reduces tobacco production cost. Accordingly, the workload which can be finished by about twenty persons through ordinary manual operation can be finished by two or three persons through the tobacco seedling under-film transplanting machine.