The invention relates to a mechanical drilling device for oil exploitation. The mechanical drilling device includes a machine body and a load-bearing column, a through hole is formed in the middle portion of the machine body in a penetrating mode, a screw hole is connected to the inner end of the middle portion of the machine body, a fixed seat is fixed on the outer side of the top of the throughhole, positioning screws are mounted around the fixed seat, a sliding groove is formed in the load-bearing column, the load-bearing column is located at the top of the middle portion of the fixed seat, a sliding column is connected to the inner end of the sliding groove, a punched hole is formed in the sliding column in a penetrating mode, a connecting hole is formed in the outer wall of the load-bearing column in a penetrating mode, and a penetrating groove is formed in the top end of the sliding column. The mechanical drilling device for oil exploitation has the advantages that the mechanical drilling device for oil exploitation is provided with a hydraulic cylinder; through the operation of the hydraulic cylinder, a connecting seat is pushed to move by a hydraulic rod, so that a supporting seat is driven to move, the supporting seat is in contact with the ground to make the machine body supported by the supporting seat, thereby achieving the goal of improving stability of the machine body.