Abstract: This paper introduces the structure design of subcritical blanket driven by ITER in detail. Along the toroidal 360 degree, the whole subcritical blanket is divided into thirty six petals. Furthermore, based on the interface of plasma chamber, each single blanket petal is divided into inner and outer parts, every part is made up of the first wall structure, supporting structure, fuel zone structure, tritium producing zone structure and zirconium cladding structure. For distinguishing the petal from the present small module blanket structure of ITER device, the inner and outer blankets are designed as a type of whole embedding structure to reduce the pipe connecting plug quantities of a large quantity of embedding coolant pressure pipes in fission fuel zone, shorten the period of changing fuel and reduce the cost. At the same time, considering the confinement of ITER device self-structure space for the subcritical blanket, a sort of converging pipe structure which can satisfy the requirements of thermal-fluid and realize project welding assembly for blanket is put forward. Finally, using software Pro/e, the blankets three dimensional CAD drawing is established in order to output the finite element computation model for mechanical analysis.