A use of recombinant ganoderma immunoregulatory protein (rLZ-8) in a preparation of a drug for treating melanoma is disclosed. By establishing experimental animal models of orthotopic tumors and metastatic tumors, an anti-tumor effect of the rLZ-8 is researched, which indicates that the rLZ-8 significantly inhibits a growth of the orthotopic tumors of the melanoma and a formation of metastases of the melanoma.