Abstract: Objectives　To investigate the effect of thyroid hormone on the expression of deiodinase and myelin basic protein in brain tissue of neonatal rats with germinal matrix-intraventricular hemorrhage (GM-IVH), and its nerve protective effect. Methods 　Sixty premature rabbits of gestational age 29 days were randomly divided into control, model and intervention groups. The premature rabbits in model and intervention groups were given intraperitoneal injection of 50% glycerol to establish GM-IVH animal model and the premature rabbits in control group were given the same dose of saline. The GM-IVH was screened by cranial ultrasound. The premature rabbits with GM-IVH in intervention group were given intraperitoneal injection of triiodothyronine and the other two groups were given the same dose of saline. At 3 days, 7 days and 14 days after birth, the premature rabbits were killed and the brain tissue were quickly separated. The expression of type 2 iodothyronine deiodinase (D2) and type 3 iodothyronine deiodinase (D3) of periventricular zone tissue were detected by western blot method. The expression of myelin basic protein (MBP) were detected by immunohistochemical method. Results　The expression of D2 in brain tissue increased gradually in three groups. At the same time point, the expression of D2 was the lowest in the model group, the highest in the control group, and the middle in the intervention group. The differences of D2 among three groups were statistically significant (all P<0.001). The expression of D3 increased gradually in the control and model groups, while it was the highest in the intervention group at day 7. At the same time point, the expression of D3 in the control group was the lowest, it was higher in intervention group than that in the model group at 3 days, then it was higher in the model group than that in the intervention group. The differences of D3 among three groups were statistically significant (all P<0.001). The expression of MBP increased gradually in the control and intervention groups, and it decreased gradually in the model group. At the same time point, the MBP was the lowest in the model group, it was the highest in the control group, and it was the middle in the intervention group. The differences of MBP among three groups were statistically significant (P<0.001). Conclusions　The expressions of D2 and MBP in the brain Tissues of premature rabbit with the GM-IVH increased while the expression of D3 decreased in some extent after thyroxine intervention.