Objective To evaluate the clinieal implication of serum procalcitonin （PCT） in patients with burn sepsis by analyzing its change.Methods Twenty-eight extensively burned patients with sepsis hospitalized from January 2012 to December 2013 were recruited in this retrospective study.These patients were divided into death group （n =12） and survival group （n =16） according to the outcome.The baseline characteristics of patients in the two groups were similar.Some conventional indexes of sepsis,including white blood cell count,percentage of neutrophils,platelet count,organ function parameters [ALT,AST,total bile acid （TBA）,creatinine,blood sodium],and acute physiology and chronic health evaluation （APACHE） Ⅱ score were compared between the two groups when sepsis was diagnosed.Serum levels of PCT of patients in the two groups were determined immediately after diagnosis of sepsis,from post sepsis day （PSD） 1 to 4,and from PSD 5 to 8.Data were processed with t test,chi-square test,and nonparametric rank sum test （Keuskal-Wallis）.Receiver operating characteristic （ROC） curve of serum PCT value was used to predict death for 28 burn patients when sepsis was diagnosed.Results There were no statistically significant differences in white blood cell count,percentage of neutrophils,platelet count,APACHE Ⅱ score,and organ function parameters between death group and survival group when sepsis was diagnosed （with t values from-0.601 to 1.726,P values above 0.05）.The serum levels of PCT in death group immediately after diagnosis of sepsis,from PSD 1 to 4,and from PSD 5 to 8 were respectively （38.5 ± 41.3）,（26.8 ± 38.5）,（19.3 ± 16.3） ng/mL,which were significantly higher than those in survival group [（6.1 ± 2.3）,（5.4± 2.9）,（4.9 ±3.6） ng/mL,with Z values from-4.364 to-2.955,Pvalues below 0.01].The total area under ROC curve of serum PCT value for predicting death for 28 patients with burn sepsis was 0.990,and 10.9 ng/mL was chosen as the optimal threshold value,with sensitivity of 91.7% and specificity of 100.0%.Conclusions Serum PCT value can be served as a vital prognostic indicator for patients with burn sepsis,which can be considered as a guide for rational use of antibiotics,also provide as a reference for treatment,in order to reduce mortality.