Abstract: Objective To explore the value of critical illness score combined with serum D-dimer(D-D)and procalcitonin(PCT)in the evaluation of infection condition in children. Methods Totally 102 infected children were divided into virus infection group(n=29)and bacteria infection group(n=73)according to infection type, and they were also divided into common infection group(n=65)and severe infection group(n=37)according to the degree of infection. At the same time, 96 healthy children were selected as control group. The critical illness score, the contents of serum D-D and PCT were compared between each group, and the value of each index in evaluation of the infection condition in children was analyzed. Results There were significant differences in critical illness score, serum D-D content and serum PCT content between two groups in bacterial infection group, control group and virus infection group(P<0.05). There were significant differences in critical illness score, serum D-D content and serum PCT content between two groups in severe infection group, common infection group and control group(P<0.05). In the evaluation of infection condition by combination of critical illness score, serum D-D and PCT, the sensitivity, specificity, positive predictive value and negative predictive value were 90.2%, 95.8%, 95.8% and 90.2% respectively. Conclusion Critical illness score combined with serum D-D and PCT has an important clinical significance in early evaluation of infection condition in children.