Objective:To discuss the significance of serum retinol binding protein in nutrition support evaluation for critical patients. Methods:A total of 68 patients in ICU of the First Affiliated Hospital of NJMU between Sep. 2013 and Apr. 2014 were chosen. The levels of serum RBP,albumin,transferrin and hemoglobin were detected and APACHE Ⅱ scores were calculated at admission and after 7-day nutrition support. Sixty-five outpatient underwent physical examination were included in the control group. Results:Levels of serum RBP,albumin,transferrin and hemoglobin in the experimental group were significantly lower at admission than those in the control group (P < 0.001),while there was a remarkable increase in serum RBP level after 7-day nutrition support than on admission (P < 0.001);transferrin and hemoglobin concentrations were increased mildly (P < 0.05) and there was no significant change in albumin (P > 0.05). Serum RBP levels were negatively related with APACHE Ⅱscores. Conclusion:Serum RBP could timely and as well as accurately reflect the effect of nutrition support as well as dynamic change of illness for critical patients.