Abstract: Thrombocytopenia is a common complication during the treatment of malignant tumors. It can lead to insufficient doses of chemotherapy drugs or delayed chemotherapy, shorten patients’ survival time, and affect prognosis. Thrombocytopenia has two types: cancer treatment-induced thrombocytopenia and tumor-associated immune thrombocytopenia. The latter is relatively rare, and its pathogenesis may be related to immune dysregulation. Current studies have shown that gene polymorphism and methylation are involved in tumor-associated immune thrombocytopenia. The pathogenesis and treatment of tumor-associated immune thrombocytopenia are discussed in this article.