Objective To analyze the risk factors for perianal infection following allogeneic hematopoietic stem cell transplantation(HSCT), and to provide a reference for the development of preventive and therapeutic strategies for perianal infections in clinical settings.Methods A total of 264 patients receiving bone marrow transplantation were selected and divided into an infection group and a non-infected group based on whether they developed perianal infections post-transplantation. Logistic regression analysis was used to explore the influencing factors of perianal infection following transplantation. Results The incidence of perianal infection after allogeneic HSCT was 19.32%(51/264). Logistic regression analysis showed that previous history of diabetes, history of perianal disease before transplantation, undergoing a second transplantation, and the time to neutrophil engraftment were risk factors for post-transplantation perianal infection，while regular use of protectants after sitz baths was identified as a protective factor (all P<0.05). Conclusion The incidence of perianal infection following allogeneic HSCT is high. Healthcare providers should consider patient′s medical history and comorbidities in their clinical assessments, especially focusing on patients undergoing a second transplantation. Particular emphasis should be placed on enhancing health education about perianal infection during the period of delayed neutrophil engraftment, and improving perianal infection protection measures，in a bid to reduce the incidence of perianal infection post-transplantation.