Abstract: Objective To analyze the clinical characteristics of early organ injury in elderly patients with severe burns and the effects on the prognosis of patients. Methods From January 2010 to August 2018, 62 patients with severe burns (43 men and 19 women, aged from 60 to 89 years at the time of admission) who were hospitalized in the Institute of Burn Research of the First Affiliated Hospital of Army Medical University (the Third Military Medical University, hereinafter referred to as the author′s affiliation), meeting the inclusion criteria, were included in elderly (E) group, and 124 patients with severe burns (86 men and 38 women, aged from 18 to 59 years at the time of admission) at the same term were included in young and middle-aged (YM) group. Treatment of patients in the 2 groups followed the conventional procedures of the author′s affiliation. The following data of patients in the 2 groups were retrospectively analyzed. (1) Fluid replacement volume and urine volume within the first and second post injury hour (PIH) 24 were recorded. The levels of hemoglobin, haematocrit, and blood lactic acid at admission, PIH 24 and 48 were recorded. (2) The creatine kinase isozyme-MB (CK-MB), total bilirubin, blood creatinine, oxygenation index, and blood platelet count at admission, at shock stage, and on post injury day (PID) 3 to 7 were collected. (3) The days of seriously or critically ill and deaths were recorded. Data were processed with chi-square test, group t test, Mann-Whitney U test, analysis of variance for repeated measurement, and Bonferroni correction. Results (1) There were no statistically significant differences in fluid replacement volume within the first and second PIH 24, and urine volume within the second PIH 24 between patients in the 2 groups (t=0.351, 1.307, 1.110, P>0.05). The urine volume of patients in group E within the first PIH 24 was significantly less than that in group YM (t=5.628, P<0.05). There were no statistically significant differences in levels of hemoglobin (t=0.011, 1.075, 0.239), haematocrit (t=0, 0.033, 0.199), and blood lactic acid (t=0.017, 1.002, 0.739) at admission, PIH 24 and 48 between patients in the 2 groups (P>0.05). (2) There were no statistically significant differences in levels of CK-MB at admission and on PID 3 to 7 between patients in the 2 groups (t=0.069, 0.001, P>0.05). The level of CK-MB of patients in group E at shock stage was significantly higher than that in group YM (t=4.017, P<0.05). There were no statistically significant differences in levels of total bilirubin at admission and on PID 3 to 7 between patients in the 2 groups (t=0.227, 0.002, P>0.05). However, the level of total bilirubin of patients in group E at shock stage was significantly higher than that in group YM (t=6.485, P<0.05). The levels of blood creatinine of patients in group E at admission and shock stage were significantly higher than those in group YM (t=4.226, 12.299, P<0.05 or P<0.01), while there was no statistically significant difference between them on PID 3 to 7 (t=0.693, P>0.05). The oxygenation indexes of patients in group E at admission and shock stage and on PID 3 to 7 [(371±16), (263±16), and (228±18) mmHg (1 mmHg=0.133 kPa)] were lower than (420±13), (327±13), and (281±17) mmHg of patients in group YM, respectively (t=5.650, 9.782, 4.856, P<0.05 or P<0.01). There were no statistically significant differences in levels of blood platelet count at admission and shock stage between patients in the 2 groups (t=0.038, 0.588, P>0.05), while the level of blood platelet count of patients in group E on PID 3 to 7 was significantly lower than that in group YM (t=6.636, P<0.05). (3) The days of seriously or critically ill and death rate of patients in group E were respectively longer or higher than those in group YM (Z=-2.303, χ²=13.676, P<0.05 or P<0.01). Conclusions In the case of the same tissue perfusion at shock stage, injuries in heart, liver, kidney, lung, and coagulation system in elderly patients with severe burns are more obvious than those in young and middle-aged patients, with more severe illness and higher mortality.