Objectives:To assess the efficacy of cord blood-assisted haploid peripheral blood stem cell transplantation (haplo-cord-PBSCT) versus unrelated donor peripheral blood stem cell transplantation (UD-PBSCT) in the treatment of malignant hematological diseases.Methods:A retrospective analysis was performed on one hundred and four patients with malignant hematological diseases who underwent haplo-cord-PBSCT and fifty-two patients who underwent UD-PBSCT at Xiangya Hospital of Central South University between January 2016 and December 2021.Results:①The median implantation time for neutrophils in the haplo-cord-PBSCT and UD-PBSCT groups was 13 (9–22) days and 13 (10–24) days, respectively ( P=0.834), whereas the median implantation time for platelets was 15 (7–103) days and 14 (8-38) days, respectively ( P=0.816). The cumulative implantation rate of neutrophils at 30 days after transplantation in the haplo-cord-PBSCT group and the UD-PBSCT group was 100% ( P=0.314), and the cumulative platelet implantation rate at 100 days after transplantation was 95.2% (95% CI 88.3% - 98.1% ) and 100% ( P=0.927), respectively. 30 days after transplantation, both groups of patients achieved complete donor chimerism, and no umbilical cord blood stem cells were implanted. ②The cumulative incidence rates of grade Ⅱ-Ⅳ acute GVHD within 100 days after transplantation in the haplo-cord-PBSCT group and the UD-PBSCT group were 29.1% (95% CI 20.1% –38.1% ) and 28.8% (95% CI 17.2% –41.6% ( P=0.965), respectively. The cumulative incidence rates of grade Ⅲ/Ⅳ acute GVHD were 7.8% (95% CI 3.6% –14.0% ) and 9.6% (95% CI 3.5% –19.5% ) ( P=0.725). The cumulative incidence rates of 2-year chronic GVHD in the haplo-cord-PBSCT group and the UD-PBSCT group were 45.3% (95% CI 36.1% -56.1% ) and 35.1% (95% CI 21.6% –44.1% ), respectively ( P=0.237). The cumulative incidence rates of severe chronic GVHD at 2 years after transplantation were 13.6% (95% CI 7.6% -21.3% ) and 12.9% (95% CI 5.1% -24.3% ), respectively ( P=0.840). ③The 2-year CIR after transplantation in the haplo-cord-PBSCT group and UD-PBSCT group were 12.8% (95% CI 7.0% –20.5% ) and 10.0% (95% CI 3.6% –20.2% ), respectively ( P=0.341), and the NRM were 14.7% (95% CI 8.4% –22.6% ) and 16.2% (95% CI 7.4% –28.0% ), respectively ( P=0.681). ④The 2-year OS rates in the haplo-cord-PBSCT and UD-PBSCT groups after transplantation were 82.2% (95% CI 74.8% –90.3% ) and 75.5% (95% CI 64.2% -88.7% ), respectively ( P=0.276). The 2-year DFS rates were 69.9% (95% CI 61.2% –79.8% ) and 73.8% (95% CI 62.4% -87.3% ), respectively ( P=0.551). The 2-year rates of GVHD-free/recurrence-free survival (GRFS) were 55.3% (95% CI 44.8% -64.8% ) and 64.7% (95% CI 52.8% –79.3% ), respectively ( P=0.284) . Conclusion:The findings of this study indicate that haplo-cord-PBSCT and UD-PBSCT have comparable efficacy and safety in the treatment of malignant hematological diseases and can be used as an alternative treatment options.