In this study, a novel and excellent structure-damping composites (PVDF&PDA-CF3D/EP) with high damping and mechanical properties were prepared by coating double layers of polyvinylidene fluoride (PVDF) and polydopamine (PDA) on the surface of the three-dimensional braided carbon fibers (CF3D). The dynamic mechanical analysis and logarithmic decrement measurements were employed to determine the damping characteristic of composites. Results show that there is an increase of approximately 160% in the damping factor of PVDF&PDA-CF3D/EP at low temperature and low strain, compared with that of CF3D/EP. The shear strength of the composites was performed to investigate the synergy effects of PVDF&PDA on the improvement in the interfacial bonding strength between fibers and epoxy matrix. Owing to the optimum of the interface, the flexural strength, flexural modulus and impact strength of PVDF&PDA-CF3D/EP increase by 22%, 11.8% and 18.1%, respectively, compared with those of PVDF-CF3D/EP. Finally, the synergic reinforcing mechanism on the damping and mechanical properties of the composites is discussed in the paper. Therefore, this work provides a general path to make good structure-damping composites which possess great potential application in the industrial field.