The invention discloses a large hollow pipe drilling machine. The large hollow pipe drilling machine comprises a base; an upright column is fixedly arranged on the base; a cross bar penetrates throughthe upright column; the cross bar is perpendicular to the upright column; the end part, close to the upright column, of the cross bar is fixedly connected with a rotating shaft of a driving motor; adrilling mechanism is fixedly arranged at one end, far away from the upright column, of the cross bar; the drilling mechanism comprises a connecting plate fixedly arranged on the cross bar, four sliding chutes I formed in the connecting plate in a cross shape, drilling machines slidably arranged on the sliding chutes I, and driving devices connected with the drilling machines through connecting rods; drill bits of the drilling machines face the outside of the connecting plate; and the driving devices are fixedly mounted on the connecting plate. The large hollow pipe drilling machine is novel in structure, can drill holes in four positions of a large hollow pipe at the same time, and is convenient to operate, so that the working efficiency is effectively improved.