To establish a rabbit model of intracerebral hemorrhage by injecting autologous arterial blood into the basal ganglia region of rabbits by stereotactic technique, then analyze the evolution of CT values after injection of blood at different time periods in order to explore the possible mechanism of the formation of blend sign. Methods: Seventy healthy rabbits were divided into whole blood group (n=50), plasma group (n= 10), and serum group (n=10) according to the different blood components injected into the brain. The whole blood group was divided into 5 subgroups with 10 rabbits per subgroup according to time interval between injections: subgroup A (1 h gap), subgroup B (2 h gap), subgroup C (3 h gap), subgroup D (4 h gap), and subgroup E (5 h gap). After the first injection of autologous arterial blood to form a hematoma, the same component of blood was injected again at different intervals into the periphery of the hematoma to form a secondary hematoma; for rabbits in the serum group and plasma group, after hematoma was formed by injection of whole blood, within the same period of time, serum or plasma was injected at positions contralateral or ipsilateral to the first hematoma. Head CT scan was performed immediately following generation of model, and CT value of different cerebral regions was recorded. The CT value of groups injected with different blood components was compared, and the CT value variation pattern between groups injected with the same components at different time intervals was assessed. Results: In the whole blood group, injection of blood at different time intervals resulted in hematoma lesions of different densities. The CT value at the low-density site was higher than that of brain tissue and cerebrospinal fluid and was similar to the blend sign. The high and low densities were also formed in the serum and plasma groups, but the low-density sites showed similar CT values as that of cerebrospinal fluid; it was not easily distinguishable and did not meet the criteria of blend sign. Conclusion: Secondary hemorrhage may be the cause of brain CT blend sign in intracerebral hemorrhage. Low-density areas may indicate initial bleeding while high-density areas may be secondary bleeding