Abstract: Umbilical cord is a linking pathway between the fetus and the mother in the pregnancy period and it provides important nutrients and oxygen. Umbilical cord is thus considered the life line. In recent years, more attention has been paid to its transplantation, which has significant treatment effects on various hematological diseases. Umbilical cord blood stem cells have strong differentiation potentials and they play an important role in regenerative medicine. This article discusses some related concepts of umbilical cord blood stem cells transplantation, cell types, clinical trials and the advantages of using umbilical cord blood stem cell as transplant source.