Abstract: A heat dissipating device made of highly efficient heat dissipating composite material consists of an aluminum heat dissipating member, and a copper heat conducting member; the aluminum heat dissipating member has many fins on one side; both the aluminum heat dissipating member and the copper heat conducting member are joined together with an alloyed interface being formed between them; each of the aluminum heat dissipating member and the copper heat conducting member has several protrusions and fitting gaps thereon, and the protrusions are fitted in corresponding fitting gap for increasing area of the alloyed interface as well as making the aluminum heat dissipating member and the copper heat conducting member grip each other.