The present invention provides a composition containing sodium butyrate and the use of same in promoting the transformation of human hematopoietic progenitor cells to human hematopoietic stem cells. During the expansion and culture of umbilical cord blood hematopoietic stem cells, adding sodium butyrate while adding cytokines can not only increase the number of hematopoietic stem cells but also increase the ability of hematopoietic stem cells to form CFU colonies, placing the hematopoietic stem cells in a state of proliferation and non-differentiation and meeting clinical transplantation needs.