The present invention provides an immune enhancer comprising at least an interferon and a granulocyte-macrophage colony-stimulating factor, and an immunotherapeutic pharmaceutical composition comprising at least an antigen and the above-mentioned immune enhancers. The present invention further discloses a preparation method of the immunotherapeutic pharmaceutical composition, the use of the immune enhancer and the immunotherapeutic pharmaceutical composition. The immune enhancer can be applied to disease and tumor treatments caused by viruses, bacteria, and other microorganisms.