The invention discloses a soil breaking device applied to a vegetable transplanting machine. An eccentric wheel is driven by power of the vegetable transplanting machine, a vibrator is driven by the eccentric wheel through a connection rod, the vibrator can generate left-right swing relative to the perpendicular direction of the ground which vegetables are planted and inserted, a soil lifting forkand a soil breaking hammer which are fixed to the front part and the rear part of the vibrator generate up-down swing along with left-right swing of the vibrator, a nail tooth type soil grinding roller is arranged under the rear part of a support, the soil lifting fork is inserted into soil at the position which the vegetables need to be planted and inserted, the vibrator can act on the soil lifting fork and the soil breaking hammer, soil can be forked and loosened by the soil lifting fork, then the forked and loosened soil is broken by the soil breaking hammer, the broken soil is inserted and broken by nail teeth on the nail tooth type soil grinding roller, and finally the soil is scrabbled and flattened by the nail tooth type soil grinding roller. The device can smash, scrabble and flatten particular or lumpy soil, so that the phenomena that the vegetables cannot be planted and inserted downwards, cannot be planted and inserted in place and are prone to lodging after being planted and inserted are overcome.