To achieve integrally stiffened tubular component, a new technology named as hydro-assisted forming was put forward, which successfully realized integral component forming. Experiment and finite element simulation were conducted to explore the practicality and formability of stiffened tube hydro-assisted forming. Based on plastic mechanics, the critical mechanics condition was analyzed and given. At last, the shape error and thickness distribution were given in detail.The results indicate that internal pressure induces not only tensile hoop stress but also "backward" bending moment, which are useful to eliminate wrinkle defect. But it is worthwhile to note that buckling defect would happen if the internal pressure was too high due to the effection of rib initial deflection. Shape accuracy is sensitive to internal pressure. Geometric error decreases as internal pressure, but increases after the internal pressure reaches a certain degree. Both welding residual stress and thermal deformation are successfully eliminated due to plastic deformation happens during hydro-assisted forming process. In view of hydro-assisted forming process, sound thickness distribution is an effortless advantage for bending deformation has less effection on thickness distribution. The maximum thinning ratio is only 5 % for hydroassisted forming, which is far less than that of tube hydroforming. At last, an integrally stiffened tubal component with ellipticity of 2 was formed successfully by hydro-assisted forming technology, which rib height reaches 10 mm.