HLA eplet mismatch became a trending topic in kidney transplantation but is not well understood in hematopoietic stem cell transplantation (HSCT). This was a small retrospective study of 7 patients who underwent their first HSCT for hematologic malignancies from unrelated bone marrow donors in a single medical center that offers HLA-DP typing (SBT method) for unrelated donors in recent years. Single allele eplet mismatch (EMM) load measured by the mismatched circulator of the HLA Epitope Registry website updated with IPD-IMGT/HLA 3.50 on June 2023. Chimerism analysis by short tandem repeats-PCR method for monitoring the state of hematopoietic stem cell transplantation (HSCT) from bone marrow samples of the recipient (post-BMT STR).The quantity of EMM in recipient-donor pairs in this study ranged from 0 to 15 in HLA class I and 0 to 13 in HLA class II; however, the chimerism percentage presented in no regular rule. The mismatched eplet quantity was not associated with a higher percentage of Chimerism analysis after unrelated bone marrow transplantation, which implied post-BMT STR could not be a moderate method to evaluate the risk of HLA eplet mismatch. This study has several limitations: a small database, and insufficient follow-up. In the future, a sufficient follow-up should evaluate other clinical outcomes to investigate the impact of HLA eplet on HSCT.