Objective: To investigate the efficacy of alternative donor (AD) in the treatment of aplastic anemia (AA) in children. Methods: The clinical data of AA children who received AD HSCT in our center from Apr. 2010 to Dec. 2016 were retrospectively analyzed. The overall survival (OS) rate, implant success rate, incidence of acute and chronic graft-versus-host disease (GVHD) were statistically analyzed. Results: A total of 109 children with acquired AA, including 64 severe AA (SAA) , 32 very severe AA (VSAA) and 13 transfusion dependent non-severe AA (NSAA) , were recruited in this retrospective AD HSCT study, the median age was 6 (0.8-18) years old. Of them, 44 patients with 10/10 matched unrelated donor (MUD) , 44 patients with mismatched unrelated donor (MMUD) and 21 patients with mismatched related donor (MMRD) . All patients did not receive ATG before HSCT and the active infection was excluded. Except 3 patients suffered from a second graft failure (2 of them rescued by second HSCT) , 106/109 (97.2%) were engrafted with neutrophil and platelet recovery occurring at a median of 13 days (range, 9-19) and 16 days (range, 10-81) post-transplant. Until day 100 post transplantation, the incidence was 74.3% (81/109) for acute GVHD (aGVHD) and 39.4% (43/109) for grade Ⅱ-Ⅳ aGVHD, 30.7% (31/101) and 9.9% (10/101) for overall chronic GVHD (cGVHD) and moderate cGVHD, respectively, and nobody developed an extend cGVHD. After median follow up of 39 (0.7-103) months for all patients, 13 of 109 patients died. The estimated 5-year overall survival (OS) of the entire cohort was 88.1% (95%CI 81.1%-91.4%) with no difference among the MUD, MMUD and MMRD cohort (93.2%, 84.1% and 85.7%, respectively, P=0.361) . Conclusion These excellent outcomes suggest that unmanipulated AD PBSC is a good HSCT source for children with SAA. It’s reasonable to consider AD HSCT as first line therapy for SAA children without matched sibling donor. Better strategies are required to prevent GVHD.