Objective To investigate the changes of imitating thrombosis-test (ITT) in vitro for the cerebral infarction patients.Methods ITT was measured in the 43 cerebral infarction cases and 51 healthy controls. The ITT before defibrase was injected in 30 cerebral infarction cases compared with that after treatment.Results The weight of imitating thrombosis and thrombus index Q of the cerebral infarction group is highter than that in control group (P0.05), but there is no signficant difference in the length of thrombus between two groups(P0.05). The length, weight of thrombus and the thrombus index Q were remarkably lower in treatment group with defibrase (P0.01).Conclusions ITT is a useful way in assessing the situation of thrombus formation in vitro.