Abstract： Objective To analyze the changes of adenoid size after hematopoietic stem cell transplantation(HSCT)in children with mucopolysaccharidosis(MPS)type Ⅰ and type Ⅱ,and to provide help for the formulation of treatment plan for children with MPS.Methods The medical records and imaging data of 14 children with type Ⅰ and type Ⅱ MPS treated with HSCT were retrospectively analyzed to evaluate the change of adenoid size.Results The clinical manifestations of the 14 patients were different.86％(12/14)of the patients had otolaryngology manifestations before diagnosis,including nasal congestion,sleep snoring,recurrent respiratory infection,earache and hearing loss.All the 14 patients were found to have adenoid hypertrophy of varying degrees by head MRI at admission(A/N＞0.6),and the comparison of adenoid size before and after HSCT showed statistically significant remission(P＜0.05).Conclusions The symptoms of otolaryngology in children with MPS appear early and are common.Upper airway obstruction is more common in MPS type Ⅰ and type Ⅱ patients,which is mainly caused by adenoid hypertrophy.Successful HSCT treatment can significantly reduce the degree of adenoid hypertrophy in MPS type Ⅰ and type Ⅱ,unnecessary adenoidectomy can be avoided.