Objective The CT values of brain tissue of premature infants are usually low and it is difficult to assess if they stand in the normal range of CT values of premature infants. This paper aims at studying the differences of brain CT values between the premature and term infants. Methods Seventy-six premature infants were divided into 2 groups according to the gestational age: 28 - 33+6 weeks group (n = 36) and 34 - 36+6 weeks group (n = 40). Fifty term infants were used as the control group. The cranial CT scan was taken and the CT values of various regions of brain tissues were measured. Results The CT values of cerebellum, brainstem, basal segment, thalamus, white matter and grey matter in the two premature infants groups were significantly lower than those in the control group ( P ＜ 0.01 ).The CT values of the above regions of brain tissues in the 28 - 33 + 6 weeks group were significantly lower than those in the 34- 36+ 6 weeks group ( P ＜ 0.01). Conclusions This study shows that the brain CT values of the premature infants are significantly lower than those of the term infants, thus the reference range of the brain CT values of full term neonates is not fit for the premature newborns.