Objective To assess the acute high altitude sickness (AHAS) and its risk factors among public health emergency responders, so as to provide scientific proof for guaranteeing the safety and health of emergency rescue workers. Methods?The self-administered questionnaire aim at learning AHAS occurrence and its risk factors were distributed to 67 members from 4 teams at different altitudes selected among 35 rescue teams. The AHAS could be diagnosed by a total score of more than or equal to 5 within 3 days since arrival, as in the following detail: 1-3 score could be assigned in accordance with the following symptoms in degrees of the mild, moderate or severe, respectively: headache, nausea or vomiting, lassitude, dizziness and blurred vision, and sleep disorder; and 1 score could be assigned for each of the following symptoms: palpitation, shortness of breath, nosebleed, chest distress, diarrhea, constipation, cyanochroia of the lips, numbness in hands and feet, and dry cough. Results?A total of 54 among 67 (81%) responders completed the questionnaire, among whom 93% were males and the median age was 36 with the scope from 24 to 55, and 63% (34 respondents) developed AHAS. The univariate analysis showed that the altitude of the responders’ original residence (10 score for “lt;100 m” vs. 5.2 score for “gt;1 000 m”, P=0.005), experiences in high altitude areas (10 score for “having not” vs. 6.4 score for “having”, P=0.039), length of stay in an area over 2 000 m altitude before arrival (9.4 score for “≥3 days” vs. 5.7 score for “≤1 day”, P=0.011), luggage weight (9.8 score for “≥25 kg” vs. 5.5 score for “lt;25 kg”, P=0.002) were correlated with AHAS severity. The multivariate linear regression indicated that the lower altitude of the responders’ original residence and the short stay in an area over 2000m altitude before arrival were the factors influencing the severity of AHAS. The linear regression formulation was Y= 2.89 - 0.187 × the altitude of the responders’ original residence (pre 100m) + 2.43 × the length of stay in an area over 2000m altitude before arriving at Yushu (day). Conclusions?The past experiences and the pre-arrival preparation are critical factors of AHAS. Measures should be taken to protect the safety and health of responders dispatched to high altitude areas.