The granulocyte colony-stimulating factor (G-CSF) plays an important role in regulating function of immunocytes in process of mobilizing hematopoietic stem cells. The deep understanding of the immunoregulatory effects of G-CSF has important significance to improve the outcomes of patients with hematological malignancies after allogeneic hematopoietic stem cell transplantation, included alleviating acute graft-versus-host disease, maintaining or enhancing graft-versus-leukemia effects and decreasing the relapse rates. In this article, the immunoregulatory effect of G-CSF on graft of peripheral blood and bone marrow, the immunoregulation of G-CSF and allo-hematopoietic stem cell transplantation, as well as the prospective trend of research on immunoregulatory effects of G-CSF were reviewed.