It has high demands on the performance and reliability of the heavy steel plate and metallurgical quality due to that vessel Hull and offshore marine platform steel plate work under harsh conditions, strict security and reliability requirements, long service life, maintenance difficulties. Steel plates used should have sufficient strength, good toughness, and fatigue resistance, anti-layered tear resistance, corrosion resistance, good weld ability. China hasn’t marine platform steel standard currently, so the heavy alloy steel plate for this platform standards used is referred to the API specification of the U.S, marine structural steel, pressure vessel steel, and also meet the standards for fixed offshore (mobile) platform.. In order to meet the needs of the domestic offshore platform steel plate, continuous technological innovation and research, XG has been investing a lot of manpower and material resources in the field of R & D and production of special thick marine platform steel. It has succeeded in developing a low carbon equivalent security performance steel plate, having a thickness of 1/2, large heat input welding offshore marine platform steel plate and it has extra-thick marine platform steel plate such as 230mm of E36 and 350mm of D36, which can meet the tough demanding requirements of the deep-sea offshore platform in the field of technical quality of steel, so that it promotes localization process of domestic offshore platform steel.