Thrombelastograghy (TEG) is an important test to assess the blood coagulation function to monitor the whole process of perioperative coagulation. TEG can evaluate the coagulation cascade, from platelet aggregation, clot strengthening and fibrin cross-linking to eventually clot lysis in small volume of whole blood. The reference range is one important element to influence the TEG results. At present, a number of studies have shown that reference range of TEG exists significant differences between different racial and geographic. At the same time, reagent manufacturers also suggested that each TEG laboratory should establish its own reference range. So it is important to establish our own reference range of TEG to guide the clinical blood transfusion and treatment.