Abstract: Chemotherapy and hematopoietic stem cell transplantation remain the primary treatment modalities for hematological malignancies. However, poor quality of life, unfavorable prognosis, and high recurrence rates continue to pose major clinical challenges for patients with malignant hematologic diseases. In recent years, targeted therapy, as a crucial component of precision medicine, has evolved into an indispensable intervention strategy in the comprehensive management of malignant hematologic diseases. Patients with hematological malignancies commonly exhibit genomic instability and abnormalities in the DNA damage repair (DDR) pathway. Among these, poly(ADP-ribose) polymerase 1 (PARP1), a key regulator of DNA single-strand break repair, shows significantly upregulated expression in tumor cells. Consequently, targeted inhibition of PARP1 has emerged as one of the most promising research directions in the treatment of hematological malignancies. To further elucidate the pathophysiological role of PARP1 in hematological malignancies, this article aimed to provide a comprehensive review of its molecular definition, biological functions in hematological malignancies, the current application status of PARP inhibitors, and the latest research advances in their mechanisms of action.