Abstract： Objective To investigate the changes of plasma fibrinolytic activity of patients in acute phase of cerebral hemorrhage and to evaluate the relationship between fibrinolytic activity and hematoma enlargement. Methods The PLG: A and the plasma D-D levels of 115 patients with cerebral hemorrhage were detected by means of synthetic ehromogenie substrate method and enzyme-linked immunosorbent assay (ELISA). The blood samples were obtained at 6 h, 12 h and 24 h respectively after onset of the disease. All of the pamameters were compared with 50 healthy subjects. Meanwhile 115 patients with cerebral hemorrhage were divided into two groups according to the definition of hematoma enlargement: patients with hematoma enlargement and patients without hematoma enlargement. The parameters of the two groups were compared. Results The PLG: A of patients with cerebral hemorrhage at 6 h, 12 h and 24 h after onset were significantly lower than those in control group(P < 0.05). The levels of D-D in plasma of patients with cerebral hemorrhage at 6 h , 12 h and 24 h after onset were significantly higher than those in control group(P < 0. 05). All of the observing parameters presented no significant difference between patients with hematoma enlargement and patients without hematoma enlargement. Conclusion Fibrinolytic activity of plasma increases and hematoma enlargement has no relation with fibrinolytic activity in acute phase of cerebral hemorrhage.