Objective: The study investigates the changes in serum ADH concentration and finds out the relationship between prognosis factors in brain trauma injury, such as sodium treatment time at Emergency Department and patients’ lives. Materials and methods: The study subjects include brain trauma patients, Glasgow Coma Scale ≤ 8, hospitalized for fewer than 72 hours at Hue Central Hospital with CT scans of the brain and diagnosis of brain trauma injury. After being tested, these patients are treated at Emergency Department. Their treatment time is counted from the first day in Emergency Department to the day their health conditions are stable and they are moved to other departments. Serious cases in which patients ask for discharge are considered as dead cases. Results: By studying the change in serum ADH concentration among 59 brain trauma patients, including 51 males (86.44%) and 8 females (13.56%), the result is as below: serum ADH concentrations at 2 times of study head trauma are different and meaningful (p<0.05). The correlation between serum ADH1 concentration and days of treatment at Emergency Department (r = 0.359, p= 0.002,  y= 0.0449x + 8.6897). Conclusion:  ADH1 concentrations > ADH2 has a statistically significant (p < 0.05). The correlation between serum ADH1 concentration and days of treatment at Emergency Department (r = 0.359, p= 0.002,  y= 0.0449x + 8.6897). The area under ROC curve of ADH2 is 75.7%, higher than that of Na+2 (73.9%).Cut-off value to predict the turn of ADH2 and Na2 was 28.61 pg/ml, 146mmol/l.