Abstract: Objective To analyze the characteristics of thyrotrophic axis and the influencing factors in patients with pituitary stalk interruption syndrome (PSIS). Methods Clinical data about 89 patients with PSIS admitted to Chinese PLA General Hospital from 2000 to 2013 were retrospectively analyzed. Results Of the 89 patients, 71 patients (79.78%) were diagnosed with central hypothyroidism based on FT4 levels lower than 10.4 pmol/L with the TSH level of 5.42±3.67 mU/L. The FT4 levels in the remaining 18 patients with no central hypothyroidism were close to the lower limit of reference range and the TSH was 3.66±1.50 mU/L. Of the 71 central hypothyroidism patients, TSH level in 29 patients (40.85%) was higher than 5.5 mU/L with a mean±SD of 8.79±3.17 mU/L, 38 patients (53.53%) was in the normal range with a mean±SD of 8.79±3.17 mU/L and 4 patients (5.63%) was lower than the normal level with a mean ±SD of 0.02±0.01 mU/L. The FT4 levels of the higher TSH group were slightly higher than that of normal TSH group, but there was no differences in statistics (7.90±1.38 pmol/L vs 8.08±1.42 pmol/L, P> 0.05). Elevated TSH level in the PSIS patients with central hypothyroidism decreased to normal after hormone replacement therapy (7.24±0.98 mU/ L vs 1.67±1.51 mU/L). TSH Level had no relationship with pituitary height and pituitary stalk (P> 0.05). Conclusion The ratio and amplitude of elevated TSH in PSIS induced central hypothyroidism patients are higher than that of the other causes of central hypothyroidism. The TSH level in PSIS patients is independent of the height of anterior pituitary and status of pituitary stalk, the possible reason is reduced thyroid hormone feedback inhibition stimulated the secretion of TSH with no biological activity.