Gastrointestinal bleeding (GIB) accounts for a significant proportion of life-threatening bleeding cases occurring after allogeneic haematopoietic stem cell transplantation (allo-HSCT). However, data on GIB after haploidentical HSCT (haplo-HSCT) are not available. A total of 3180 patients received haplo-HSCT at Peking University People's Hospital from January 2015 to November 2019, and GIB occurred in 188 of these patients (incidence of 5.9%). Platelet counts <30 × 109/L, viral hepatitis, acute kidney injury (AKI), gastrointestinal disease or bleeding before HSCT and sinusoidal obstruction syndrome (SOS) were determined to be significant risk factors for the occurrence of GIB after haplo-HSCT. Grade III-IV acute graft-versus-host disease (aGVHD), AKI, thrombotic microangiopathy (TMA), disseminated intravascular coagulation (DIC) and gastrointestinal disease or bleeding before HSCT were significantly related to mortality in patients with GIB after haplo-HSCT. The predictive models developed for the occurrence and mortality of GIB performed well in terms of discrimination, and they might assist clinicians with personalised strategies for GIB prevention and treatment in patients after haplo-HSCT.