The invention belongs to the technical field of biological medicines, and particularly relates to application of an
antiviral drug acyclovir in preparation of a tumor
immunotherapy drug. According to the invention, acyclovir is utilized to induce macrophages to become an M1
phenotype, the phagocytic function and the
antigen presentation capability of the macrophages are enhanced, and the maturation of dendritic cells is promoted, so that the anti-tumor effect is realized. In an effective concentration which is non-toxic to a macrophage line RAW264.7, acyclovir significantly promotes
phenotype transformation of macrophages to M1, and significantly enhances the
cell phagocytic ability and
antigen presentation ability of the macrophages. Meanwhile, the acyclovir in an effective concentration can also remarkably promote maturation of
bone marrow-derived dendritic cells, so that new application of the acyclovir in the field of tumor
immunotherapy is found. According to the method, the application range of acyclovir and immune
cell immunotherapy is expanded, and a new feasible
clinical treatment scheme is provided for anti-tumor immunotherapy.