The aim of this study was to investigate the effect of haploidentical allogeneic bone marrow or peripheral blood hematopoietic stem cell transplantation (allo-HSCT) combined with umbilical cord blood mesenchymal stem cell (MSC) infusion in treatment of severe aplastic anemia (SAA). Five SAA patients received haploidentical allo-HSCT combined MSC infusion. HSC and MSC were collected from bone marrow or peripheral blood of haploidentical donors and umbilical cord blood respectively. After transplantation, the clinical hematopoietic reconstitution and early complications were monitored. The results indicated that all the 5 patients achieved hematopoietic reconstitution. The average time for WBC count > 2×10(9)/L was 13.8 days, and average time for Plt level > 20×10(9)/L was 17.8 days. The STR-PCR detection of patient peripheral blood at day 30 after transplantation showed that engraftment was complete donor's gene type. The communication with 1 patient was broken off because of his epilepsy, other 4 patients are all alive in diseases-free state. In conclusion, the haploidentical allo-HSCT combined with umbilical cord MSC infusion is an effective approach to cure SAA, which needs to be further studied in a large number of cases.