Background: Long-term health-related quality of life (HRQoL) of pediatric patients after hematopoietic stem cell transplantation (HSCT) is increasingly studied worldwide. However, few studies have been performed in China, where no uniform scale is available; the PedsQL (TM) Cancer Module 3.0 Chinese Mandarin version has been used to evaluate HRQoL of patients after HSCT in China. This study aimed to assess the reliability and validity of the Chinese Mandarin version of PedsQL (TM) 3.0 Transplant Module. Methods: Patients between 2 and 18 years old, who underwent HSCT from January 2006 to June 2014, were recruited in Beijing Children's Hospital affiliated to Capital Medical University, the First Affiliated Hospital of Southern Medical University and Beijing Daopei Hospital. 207 parent reports and 182 child self-reports of the PedsQL (TM) 3.0 Transplant Module Chinese Mandarin version were assigned, of which 362 were returned. Results: No missing item response was observed in the returned reports. Cronbach's alpha coefficient exceeded 0.7 in total scale and every dimension. The intraclass correlation coefficient exceeded 0.8 in all dimensions of child self-reports and parent reports. Spearman's rank correlation coefficients of items and their respective dimensions were 0.6-0.94 in parent reports, and 0.62-0.93 in child self-reports, while a weak association was found between the items and other dimensions. Exploratory factor analysis indicated a good extraction effect, and construct validity of the scale was >60 %. Conclusions: The Chinese Mandarin version of PedsQL (TM) 3.0 Transplant Module has good feasibility, reliability and validity. Its use may help improve the HRQoL of children after HSCT in China.