Abstract: Entire 3D design has been widely used in offshore platform design. In this paper, with the design of a jacket platform in East China Sea as an example, the advantages of entire 3-D design, the procedure and the factors to be considered in the entire 3D design have been discussed. A lot of practical experience has been summarized, and some problems during design have been analyzed, such as incompatibility between different software, collide of pipeline and equipment.The ways and methods to solve these problems will be very helpful in future entire 3D design of offshore platform.