Abstract: Carbon nanotubes/aluminum (CNTs/Al) composite powders were prepared by both wet ball milling and dry ball milling. CNTs/Al composites were fabricated by using a sparking plasma sintering (SPS) combined with a hot extrusion process, and the relationship between preparation process-microstructure-mechanical properties was explored systematically. The results show that wet ball milling can better disperse CNTs than dry ball milling, and significantly reduce the damage to the structure of CNTs. The ethanol ball milling medium has a cooling effect that is helpful to significantly refines the grain size while reducing the cold welding of the powders, resulting in excellent mechanical properties of the composite. The tensile strength of 2%CNTs/Al composites sintered and hot extruded after 6 h wet ball milling reached 207 MPa.