The effects of human lactoferricin (LfcinH) and bovine lactoferricin (LfcinB) on the proliferation and cytokine secretion of spleen lymphocytes in mice were studied, and the differences and correlation between LfcinH and LfcinB were compared and analyzed, respectively. The cell counting kit-8 (CCK-8) assay was used to measure the effects of different concentrations of LfcinH or LfcinB alone on the proliferation of mouse spleen lymphocytes and of different concentrations of LfcinH or LfcinB combined with a mitogen on the proliferation of mouse T and B lymphocytes. The IL-2, IL-4, TNF-α content was determined by enzyme-linked immunosorbent assay (ELISA). The results showed that LfcinH and LfcinB could significantly promote the proliferation of spleen lymphocytes and enhance the T lymphocyte proliferation induced by concanavalin A (ConA) and B lymphocyte proliferation induced by lipopolysaccharide (LPS). Moreover, Lfcin could significantly increase the secretions of IL-2, IL-4, TNF-α in spleen lymphocytes. The results also showed that Lfcin has a synergistic effect on the proliferation of T and B spleen lymphocytes with Con A or LPS; the mechanism may be related to the immune enhancement achieved by promoting cytokine secretion.