This study was purposed to analyse the clinical efficacy of transplantation of umbilical cord mesenchymal stem cells (UC-MSC) combined with haploidentical hematopoietic stem cells (haplo-HSCT) for patients with refractory/relapsed myeloid leukemia. The clinical data of 36 patients received transplantation of UC-MSC combined with haplo-HSCT from January 2007 to June 2013 were summarized retrospectively, the engraftment, GVHD and 2 years-overall survival (OS) were analysed. The results showed that the median times of neutrophil count>0.50×10(9)/L and platelet count>20×10(9)/L were 12.0 days and 14.0 days, respectively. Grade III to IV aGVHD occurred in 5 out of 36 patients (13.8%). cGVHD occurred in 12 out of 32 patients (37.5%) and extensive cGVHD occurred in 2 patients. Additionally, only 3 patients (8.3%) experienced relapse. The 2-year OS rate of patients was 76.9%. It is concluded that the transplantation of UC-MSC combined with haplo-HSCT has good therapeutic efficacy for patients with refractory/relapsed myeloid leukemia, and may be served as a therapeutic method especially for patients with high risk and without well matched donor.