The invention relates to an offshore drilling base plate which is a deep sea offshore drilling base plate capable of automatically keeping the verticality of the axis of a drilling hole in the descending and placing processes. The offshore drilling base plate comprises a base plate body with the drilling hole, a supporting pillar arranged under the base plate body and a lifting device arranged on the base plate body, wherein at least three stretchable supporting pillars are distributed on the outer side of the drilling hole, and the axes of the supporting pillars are parallel with the axis of the drilling hole; the lifting device comprises a steel wire rope, two lifting pulleys and at least one guide pulley, wherein the lifting pulleys and the guide pulleys are all fixed pulleys located on the outer side of the drilling hole, the axes of the two lifting pulleys on the outer side are orthogonal with a cylindrical face with the axis of the drilling hole as the axis, the axes of the guide pulleys are parallel with the axis of the drilling hole, and when the steel wire rope penetrates through the lifting pulleys and the guide pulleys for lifting, the axis of the vertical part of the steel wire rope and the axis of the drilling hole are coplanar; when the two ends of the steel wire rope lift the offshore drilling base plate, the gravity center of the offshore drilling base plate is located on the axis of the drilling hole.