Abstract: Objective To study the methods for prevention of ear barotraumas by measuring and analyzing the relation between eustachian tube ventilation resistance and middle ear barotraumas in pilots. Methods Eustachian tube ventilation resistance in 80 and 30 fighter pilots after grounding was tested using a eustachian tube ventilation resistance measuring device and in a hypobaric chamber,respectively,and compared with the controls. Results Of the 220 ears,28（12.7%）were found to have middle ear barotraumas.The pilots could not balance their negative pressure in the tympanic cavity by opening mouth and swallowing.The average eustachian tube ventilation resistance was 4.1±2.0kPa,92.7% of which was less than 6.0kPa. Conclusion No barotraumas occur in ears of 92.7% of pilots when the pressure on nasopharynx is 6.0kPa.Fighter pilots can use face masks to increase the pressure or use Valsalva by changing their mask structure.