Abstract: With the innovation and upgrading of oil drilling equipment technology, the conventional small-size casting sheave can no longer meet the needs of the new era because of the blank cycle, unavoidable casting defects and environmental protection requirements. Therefore, large-size forged and welded double web sheaves are born. Combined with the real case of large-size double web sheave successfully applied to an offshore drilling platform in China, the details structure of the double web sheave is described in this paper. The stress of sheave is calculated and analyzed by ANSYS, the obtained real data of factory manufacturing and dynamic balance test provide basic experience for the design and production of large-size double web forged and welded sheaves in the later stage of the industry.