The invention discloses a novel three-dimensional interconnected CNTs/Cu composite material and a preparation method thereof. A three-dimensional porous structure is pre-pressed and sintered through discharge plasma, CNTs in-situ generation is achieved through a water-assisted chemical vapor deposition (CVD) method, and finally the CNTs/Cu composite material is prepared through an SPS. The prepared composite material is excellent in properties like electrical conductivity and intensity and can be used in the fields of electrical appliances and electronics, the preparation method is simple andlow in cost, and the preparation process is easy to implement and control.