The superplastic forming process of the core was simulated by using the finite element software, to obtain the thickness distribution and the pressure-time curves. The four-sheet structure rudder of Ti60/TA15 alloy was obtained at 920℃. The thickness of the rudder was investigated. The results show that the minimum thickness is 1.24mm and the maximum thickness is 1.80mm. The moulding surface for the four-sheet structure rudder of Ti60/TA15 alloy was measured by using the 3D scanning. The results show that the tolerance of more than 90% is less than ±0.2mm, and the global is less than ±0.5mm. The interface of diffusion bonding was investigated by the metallograph observation. The results show that at 920℃, interfaces of diffusion bonding between the same materials of TA15 and between the different materials of TA15 disappear basically, and no holes can be seen at the three diffused interfaces.