Objective: To evaluate the clinical significance of platelet aggregation rate and thrombotest parameters in severe burned patients. Methods: According to the severity of the usual burn classification standard, 87 cases of severe burn patients were divided into the 2 groups: the severe group (52 cases) and the special severe group (35 cases). The levers of 0 day, 1 day, 2 days, 3 days, 4 days, 5 days, 6 days of platelet aggregation rate (PAGT:MAR), D-dimer (D-D), fibrinogen (Fbg), antithrombin III (AT-III) activity, platelet (PLT) were observed. At the same time, 100 healthy subjects served as normal control group. Results: The levers of PAGT:MAR, PLT 0, 1 day in the two severe burn groups were significance higher than control group (all P<0.01), and these 2–6 days were significance lower than control group (all P<0.01). The levers of Fbg, AT-III activity 0, 1 day in the two severe burn groups were significance lower than control group (all P<0.01), and these 2–6 days were significance higher than control group (all P<0.01). But the levers of D-D in the two severe burn groups were always significance higher than control group (all P<0.01). There were no significant differences about PAGT:MAR, D-D, Fbg, PLT and AT-III between moderate and mild burn patients and controls between 0 and 6 days after admission (P>0.05). Conclusion: The changes of platelet aggregation and thrombotest parameters in patients with severe burn injuries may reflect the dysfunction of coagulation system and fibrinolytic system. They may provide the basis for treatment and prognosis.