Abstract: Objective To investigate the effect of prone ventilation on the oxygenation level of patients with severe coronavirus disease 2019 (COVID-19) and dyspnea. Methods Patients with severe COVID-19 complicated dyspnea admitted to Wuhan Huoshenshan Hospital from February 9,2020 to March 16,2020,were selected as research subjects.According to the posture taken during treatment,1:1 pairing was carried out.Patients in the control group were treated in the supine position,and patients in the experimental group were treated in the prone position.The changes in ventilation parameters and some physiological indicators of the two groups at different time points were compared. Results Of the 52 patients enrolled in our study,there were 12 males and 14 females in the control group,with an average age of 45.23±6.5 years,and 15 males and 11 females in the experimental group,with an average age of 52.14±5.2 years;there was no significant difference in age and sex between the two groups.Before treatment,at 1 h,6 h and 12 h,the oxygen partial pressure in the experimental group was 78.6%±6.1%,97.7%±6.0%,102.7%±7.1%,111.3%±7.4%,while that in the control group was 79.3%±5.2%,83.9%±4.6%,89.5%±5.7%,84.9%±5.2%,respectively;the oxygenation index of the experimental group was 123.9±2.6,166.1±8.2,186.6±7.9,193.1±8.2,while that of the control group was 121.1±6.8,135.0±7.6,146.3±7.5,141.9±7.4;the pulse oxygen saturation of the experimental group was 88.4%±4.9%,97.4%±6.9%,97.9%±8.0%,98.1%±7.3%,while that of the control group was 87.9%±4.1%,94.1%±6.0%,93.1%±6.4%,94.5%±6.2%;after treatment,the oxygen partial pressure,oxygenation index and pulse oxygen saturation of the experimental group were superior to those of the control group (all P<0.05).There was no statistically significant difference in heart rate,mean arterial pressure,and central venous pressure at 1 h,6 h,and 12 h (all P>0.05).There were 7 deaths in the control group,and 9 deaths in the experimental group,without statistically significant difference in mortality between the two groups (P>0.05). Conclusion Adopting a prone position for ventilation can effectively improve the oxygenation level of critically ill patients,without increasing the cardiac burden of patients,but it has little significance in reducing the mortality of such patients.