Objective: To investigate the predictive value of B type natriuretic peptide in evaluating fluid volume in the patients receiving fluid resuscitation with early phase of septic shock, and to find the relative markers of fluid volume which can accurately reflect the blood volume of septic shock. Methods: A prospective study was performed on 60 patients with septic shock enrolled in the intensive care unit of our hospital. All the patients receiving early goal-directed therapy(EGDT), the hemodynamic parameters such as intrathoracic blood volume index(ITBVI), global end diastolic volume index(GEDVI), extravascular lung mater index(EVLWI) were record by using PICCO system before and after EGDT, and the parameters of BNP were record at the same time. The correlations between changes in BNP and changes in ITBVI,GEDVI and EVLWI were tested by Pearson correlation analysis． Results: ITBVI,GEDVI and BNP in all patients were significantly elevated after EGDT. BNP level was not correlated with ITBVI,GEDVI and EVLWI at the time point 0 h and 6 h in the 60 patients receiving fluid resuscitation. The changes in BNP (ΔBNP) showed significant correlation with changes in ΔITBVI and ΔGEDVI. ΔEVLWI was not correlated with ΔBNP. Conclusion: The predictive value of B type natriuretic peptide in evaluating fluid volume in the patients receiving fluid resuscitation with early phase of septic shock is uncertain.