Abstract: Used a formula developed by auther,the daily moist available energy in East Asia is computed from May to July in 1991.The evolution characteristics of the moist available energy and its relation with the three rainy intervals are briefly studied.The main results are as follow:1) The evolution characteristics of the moist available energy in the East Asia can reveal the season change from spring to summer.2) The evolution of moist available energy over the Yangtze-Huaihe River oscillated obviously,the moist available energy is low in the pre-maiyu period but high during the maiyu preiod.3) There are three periods of torrential rain which correspond with the peaks of the moist available energy over the Yangtze-Huaihe River.