By observing and analyzing the influence of endurance training on running economy(RE) and maximal oxygen uptake,this research aims to discuss value of RE index in expressing the effect of endurance training.42 soldiers were given a 10-week endurance training of 5 kilometer running and their indexes of VO2max and RE were measured before and after each training.To evaluate the importance of the indexes in endurance training effect by the method of main composition analysis,the 5 kilometer long distance running training led to increase of 4% in R-VO2max,and the noticeable decrease in RE(3.0%~9.0%,P0.05).The result indicates that RE,compared to VO2max,has more noticeable sensitivity in evaluating the effect of endurance training,that the contribution rate of RE index is in the relative important position in expressing the effect of endurance training,whereas the VO2max,the contribution rate of RE plays most important role in expressing the effect of endurance training.The index of RE is superior to that of VO2max in evaluating the effect of t average people′s endurance training.