Purpose: This study was a prospective longitudinal study to identify changes in quality of life in patients undergoing allogeneic hematopoieticstem cell transplantation (HSCT). It was based on Roy’s adaptation model. Methods: The questionnaires were administeredbefore HSCT, 30 and 100 days after HSCT. Of the 48 potentially eligible patients, 44 (91.7%) participated in the study and 40(90.9%) completed the questionnaires at 100 days after HSCT. Multilevel analysis was applied to analyze changes in quality of life. Results: Overall, quality of life showed a decreasing tendency from pre-HSCT to 100 days after HSCT. The adaptation level of participantswas compensatory. Type of conditioning was the significant factor influencing quality of life before HSCT (β00=79.92, p qqqlt;.001;β01= - 12.64, p qqqlt;.001) and the change rate of quality of life (β10= - 1.66, p =.020; β11=2.88, p =.014). Symptom severity (β20= - 1.81,p =.004), depression (β30= - 0.58, p =.001), social dependency (β40= - 0.35, p =.165), and loneliness (β50= - 0.23, p =.065) had a negativeeffect on changes in quality of life. Symptom severity and depression were statistically significant factors influencing changes inquality of life. Conclusion: According to the results of this study, the development of nursing intervention is needed to improvequality of life in patients undergoing allogeneic hematopoietic stem cell transplantation in the early immune reconstruction period. The interventions should include programs to enhance coping capacity and programs to help control symptom severity and depression. Also these interventions need to be started from the beginning of HSCT and a multidisciplinary approach would be helpful.