Abstract: Objective To study the APACHEⅡscore in predicting the prognosis of patients with exertional heat stroke(EHS). Methods Fifty-four EHS patients(43 survived and 11 died) admitted to 10 Chinese PLA hospitals were included in this study. Their poorest indications within 24 h after admission were scored according to the APACHEⅡscoring scale and APACHEⅡscores in predicting the prognosis of EHS patients were analyzed according to their ROC curves. Results The APACHE II score was 2-39(19.70±10.63) for the 54 EHS patients. The score was significantly higher for the survived patients than for the died patients(30.82±5.50 vs 16.86±9.73, P <0.001). The APECHEⅡscore was 0.890±0.044 in predicting the death of EHS patients according to the area under the ROC curve and the optimal APECHEⅡscore was 25.5 in making the diagnosis of EHS with a sensitivity of 90.91% and a specificity of 83.72%. Conclusion APECHEⅡscore can predict the severity and prognosis of EHS patients. However, attention should be paid to those with a low APECHE Ⅱ score.