The invention discloses a protein for regulating macrophage immune function activity and application thereof, and belongs to the field of biotechnology. The amino acid sequence of the protein is shownin the sequence table SEQ ID NO. 1. The application of the PvEXP100 protein in regulating macrophage immunity is screened and verified for the first time. The PvEXP100 protein acts on unactivated RAW264.7 macrophages, the capability of secretion of NO, IL-2, IL-6 and TNF-alpha by RAW264.7 macrophages can be remarkably improved, the mRNA levels of the IL-6, the TNF-alpha, the IL-2 and iNOS are increased by 8.2-47.72 times respectively, and the protein has broad application prospects.