Objective To investigate the significance of early diagnosis and prognosis of central diabetes insipidus(CDI) caused by sellar tumor surgery or severe traumatic brain injury.Methods Forty-eight cases patients of CDI caused by sellar tumor surgery or severe traumatic brain injury hospitalized in our hospital were selected. These patients were divided into 3 groups. Group A:transient diabetes insipidus. Group B: persistent diabetes insipidus. Group C: triphasic diabetes insipidus. Laboratory markers were measured before and after treatment, and prognostic analysis was performed.Results Serum sodium and osmolality, 24 urinary sodium level and 24h urine volume of group A and C, decreased after treatment, the statistical differences were significant (P<0.05 or P<0.01). Serum osmolality, 24h urinary sodium of group A and C decreased than group B (P<0.05). In the aspect of GOS score after treatment, the ratio of patients scored 4 points or below in group B and group C was significantly higher than group A (P<0.05). The ratio of patients scored 5 points in group B and group C was significantly lower than in group A. All patients were followed up for one year, and the patients in group A had a significantly better survival than those in group B and group C (three cases died in each group) (P<0.05). In group B and group C, the postoperative level of antidiuretic hormone (ADH) initially decreased and then increased, but did not reach the normal level; in group A, the level of ADH increased initially andthen decreased, and finally reached the normal level.Objective The prognosis of patients with CDI after sellar tumor surgery or associated with severe traumatic brain injury is related to serum ADH level, and 24h urine volume.There are some differences in prognosis and survival between different types of CDI.