Semi-submersible drilling platform with Corrosion Resistant Alloy Pipes excellent performance and a larger anti-wave variable loads and drilling in the deeper waters. At that time only a few countries in the world can build, and expensive. In order to adapt to China's actual conditions designed continental shelf of semi-submersible drilling platform, three units of the designer a large collection of hydrological and meteorological data, and through in-depth practical investigation crossover drilling of five kinds  of rigorous screening program was finally officially confirmed rectangular semi-submersible drilling platform solution. The main performance parameters; water depth of 35 to 200 m, the maximum drilling depth of 6000 m.