In May 1975, one female mountaineer and eight male mountaineers of our country once more climbed onto the highest peak of the world Mount Qomolangma from the north slope. At the same time, we recorded 15 electrocardiograms while they were climbing from 7,600 m to the peak(8,848.13 m) through radio-operated electrocardiography.In this report we mainly analyze the characteristics of electrocardiogram of six mountaineers who ascended the peak at the stage from 50m a. s. l. to over 8,200m a. s. l. The result proves that although obvious changes after reaching an altitude above 8,200 m from the plain region should be those of indexes of heart rates, the QRS axis, Q-T, Q-T/T-Q, P wave and T wave, there is no T wave diphasie, inverted, flat or abnormal shifting of S-T segment in the electrocardiogram of these outstanding mountaineers. This fully proves that those summit climbers are of excellent constitution and good adaptation ability to hypoxia. This also shows that the people who have been trained and acc