The High-Altitude Hematology Observation-Stem Cell Transplantation (HALO-SCT) study is the first prospective real-world cohort of hematologic diseases and transplantation in the Qinghai-Tibet Plateau. Patients undergoing hematopoietic stem cell transplantation (HSCT) at Qinghai University Affiliated Hospital, together with their donors, are systematically enrolled. The registry collects demographic, diagnostic, treatment, prognosis, and medical expense information, as well as biospecimens for future analyses. Historical data are incorporated, and prospective data collection is ongoing with long-term follow-up planned. The registry is designed as a sustainable research infrastructure to provide comprehensive data on disease incidence, treatment patterns, outcomes, and resource utilization in a high-altitude setting.