The invention discloses a crushing device for coal mining. The device comprises a sliding rail, a sliding groove, a supporting plate, a fixed bolt, a rotating shaft, a first rotating cylinder, a firstbevel gear, a first electric motor, a placing trough, a second bevel gear, a sliding frame, a fixed shaft, second rotating cylinder, a linear motor, a fixed block, a fixed column, a roller, a rotating column, a connecting block, a connecting rod, a fixed rod, an electric push rod, a pressure plate, a fixed shell, a second electric motor, a knife seat, a coal mining knife, a fixed seat, a fixed bar, a baffle, a conveyor belt and a third electric motor. The crushing device for coal mining is simple in structure and novel in design, is convenient for workers to adjust the placing position of thedevice, and at the same time, is convenient to stably fix the adjusted device so as to ensure stable mining of the coal mining knife, and is convenient for the position adjustment of the coal miningknife so as to improve the using range of the device, and is convenient for the linear motor to stably push a sliding frame to move stably so as to make the using convenient.