Abstract： Cord blood is the main source of stem cell outside of bone marrow and peripheral blood, and cord blood transplantation, especially unrelated cord blood transplantation (UCBT) has been widely used. The major challenges in UCBT are delayed engraftment and graft rejection. Many approaches have been investigated to enhance collection of HSC and HPC in cord blood units, sinduding use of double unit UCBT, adopt reduced intensity conditioning (RIC) approach, amplification of cord blood cells in vivo or ex vivo, and co-infusion with a haploidentical T cell depleted graft or mesenchymal stem cells (MSC), or injecting cord blood cells directly into the bone marrow. Those approaches may greatly increase the clinical use of cord blood cells for transplantation.