Abstract: The tensile strength of carbon fiber/LD2 aluminum alloy (C/LD2). and graphite M40/LD2 aluminum alloy (bI40/LD2) composites at high.temperature has preliminarily investigated.Carbon fiber(C), graphite fiber (M40) and Al foil (LD2) are used as the components of composites.The C or M40/Al composite wires are fabricated by means of C.V.D.Ti-B coating on the fibers and then infiltrated with the molten aluminum alloy. The C or M40/LD2 unidirectional composite plates are prepared by partial-liquid phase hot pressing method.Experimental results have shown that the Al₄C₃ content in C/LD2 specimen is larger than that of M40/LD2.On the contrary the tensile of M40/LD2 is higher than C/LD2.But both M40/LD2 and C/LD2 composites retain the tensile strength from room temperature up to 400℃ in nearly same level.The tensile strength maintenance ratio of C/LD2 is about 84%.