Hypo-atmospheric-pressure plasma was utilized to pretreat 8-shape three-dimensional (3D) woven fabric of glass fiber. After that, the bending property of composite reinforced by the 8-shape 3D woven fabric was researched. The results showed that the composite of pretreated time 1 min had maximum onset fracture load, while the composite of pretreated time 3 min had minimum onset fracture load. Moreover, the displacement of all samples was over 4 mm. By observing the scanning electron microscopy images of the fibers peeling from the composites, it could be found that the surface of the fiber became coarse after the 8-shape 3D woven fabrics were pretreated by atmospheric-pressure plasma. The coarse surface improved interfacial adhesion between fibers and resin; consequently, the onset fracture load of the composite was improved.