In this paper, the reentry drilling systems on board of America’s “Glomar Challenger” drill ship, “JOIDES Resolution” drill ship and Japan’s “Chikyu” drill ship are investigated. This paper introduces the status of reentry drillingtechnology, the composition of the reentry drilling system, the process flow and application of reentrydrilling in ocean drilling. The reentry drilling system and the reentry method adopted on the “Challenger” and the “JOIDES Resolution” drill ship have been verified by a lot of practices, which may provide full reference for design and manufacture of the drill ship for China.