This paper aimed to solve the problems in the manufacturing process for typical T-stiffened composite structure, including difficulty to be filled of the T-stiffened area, complex and unrepeated of the process. A novel approach of vacuum-assisted liquid molding co-curing process was developed to manufacture the T-Stiffened composite structure with foam cores filled in the stiffened area. Two custom tools were designed in the new approach. During plying procedure, a well-tailored foam core and a ply-guiding plate were used to realize the precise dimension and quality control of the Tstiffened area. In the injection process, a steel pressure plate was introduced, which helped to get double-sided smooth Treinforced panel using a single-side mold. The manufactured T-stiffened panel was demonstrated to be good in quality. The results are of great reference value for the applications and developments of low cost integral manufacturing technic for stiffened structures on airplanes.