Abstract： Myeloproliferative neoplasms (MPN) are a group of diseases with malignant cloning in hematopoietic stem / progenitor cells. The main clinical feature is excessive proliferation of one or more lineage of myeloid cells, which cause increasing count of erythrocytes, granulocytes and platelets in peripheral blood.Arterio-venous thrombosis and complications are responsible for the mortality of MPN. Low molecular weight heparin (LMWH) is a kind of anticoagulant that commonly used for its safety and validity. It can improve the hyperviscosity of blood , affect platelets, and interact with leukocytes and endothelial cells, by which can reduce cells aggregation. LMWH can effectively play an active role of anticoagulant in high-platelet plasma. All of these provides a theoretical basis to its availability in MPN.