Blood transfusions were frequently in massive burn patients, current studies focus on the trigger threshold of red blood cell transfusion, and few studies focus on the impact of red blood cell transfusion volume on patient outcomes. We initiated a multicenter cohort study to explore the impact of red blood cell transfusions volume on patient mortality. 379 patients in three centers were enrolled to the cohort. The extroperative and overall RBC transfusion in the death group were significantly higher than those in the survival group (p <
0.001), and this difference became insignificant within the operation (p = 0.312). RBC transfusion volume and mortality risk of patients was obviously not linear (p <
0.0001) and would be L-shaped, and the threshold would be 6U. 1:1propensity matching was used to adjust the burn area, full thickness burned area and inhalation injury. There was no significant difference in the outcome and bloodstream infection between the two groups, but the length of stay, length of stay in burn ICU and mechanical ventilation time of the low red blood cell group were significantly lower than those of the high red blood cell group. Our findings therefore support the approach of a restrictive transfusion strategy in severely burned patients. This also confirms the scientificity of restrictive transfusion strategy and suggests that unnecessary red blood cell transfusion should be avoided in clinic.