Abstract: Currently, the role of urokinase plasminogen activator system (uPAs) in the occurrence and development of acute myelocytic leukemia (AML) has become a hot topic in clinical researches. The association of uPA to its receptor triggers the conversion of plasminogen into plasmin. This process is regulated by the uPA inhibitors (PAI-1 and PAI-2). On one hand, the activated plasmin promotes the degradation of basement membrane and extracellular matrix (ECM) components; on the other hand, it could activate ECM pro-matrix metalloproteinases (Pro-MMP) and growth factor (GF), thus contributing to the leukaemic cells extramedullary disseminations, metastasizing and proliferation. What's more, as one of the main components of fibrinolytic system, uPAs over-expression is associated with hyperfibrinolysis, leading to increased bleeding complications. This paper mainly summarizes the structure of uPAs and its contribution to the occurrence, development as well as treatment of AML.