The invention discloses a cylindrical semi-submersible drilling platform. The cylindrical semi-submersible drilling platform comprises a buoyancy tank, a cylinder body and a deck from bottom to top insequence, wherein the buoyancy tank and the deck are arranged at the two ends of the cylinder body; the cylinder body is a double-layer cylinder, four through holes are formed in the wall surface ofthe cylinder body, every two through holes are symmetrical, and a stand column is formed by the part between every two adjacent through holes; each through hole is formed by two semi-circular holes inthe two ends and a square hole in the middle in the longitudinal direction of the cylinder. With the adoption of the opening pontoon (namely, the double-layer cylinder body) and the internally and externally extending annular buoyancy tank, the heave plate has a large area, the cylindrical semi-submersible drilling platform can reduce heaving amplitude and improve heaving performance as comparedwith a semi-submersible type drilling platform, can reduce weave load, reduce mooring force and improve movement performance of the platform as compared with a round platform, and can meet the requirement of drilling operation of the platform under harsh marine environmental conditions such as South China Sea and the like.