Using good inter-laminar property of three-dimensional braided composite to meet the requirement of the integral T-joints structure, a T-joints structure has been designed and manufactured with using resin transfer liquid composite molding and 3D six-directional braided composites. The pull-off damage property of the T-joints structure has been studied by tests for different braiding angles (20°, 30°, 40°) and yarns (6k, 9k, 12k). It has been shown by the tests that the damage type of T-joints structure with 3D six-directional braided composites is the web pulling away from the flange; The T-joints structure pull-off strength increased by 53% when braiding angle changing from 20° to 40° for the same braiding yarns and by 8% when braiding yarns changing from 6k to 12k for the same braiding angle. The research results can be an important experimental guidance for the design and development of integrated composite structure.