Objective To construct a scoring system of combination of procalcitonin and C-reactive protein for diagnosis of invasive bacterial diarrhea in children. Methods The clinical data of hospitalized children with acute diarrhea were retrospectively analyzed. All of the children were divided into two groups, invasive bacterial diarrhea group and nonbacterial diarrhea group. The scoring system of combination of two markers for diagnosis of invasive bacterial diarrhea in children was constructed by means of two categories logistic regression analysis using procalcitonin and C- reactive protein as parameters. In addition,receiver operating characteristic curve(ROC)was used to evaluate the diagnostic accuracy.Results One hundred ten cases of invasive bacterial diarrhea and 108 cases of nonbacterial diarrhea were included. The levels of serum procalcitonin and C-reactive protein in invasive bacterial diarrhea group were significantly higher than those in nonbacterial diarrhea group, and there were statistical difference(P all<0.05).The area under the ROC curve(AUC)of invasive bacterial diarrhea was 0.894 when the established scoring system was used, which was higher than the AUCs when either serum procalcitonin or in C- reactive protein was used (P<0.05). The best diagnostic boundary value for combination of serum procalcitonin and C- reactive protein scoring was 0.52 with a sensitivity at 80.9% and specificity at 88.9%. Conclusions The scoring system of combination of procalcitonin and C- reactive protein has good accuracy in diagnosis of invasive bacterial diarrhea in children, and can assist the early diagnosis of the disease.