The motion assist method is investigated in the case of daily action of elderly people whose muscle forces decline or nursing hard work. Full-body suit with the elastic elements along the muscle which acts motion assist function seems to assist the muscle load. In this study, we examined the methods used to evaluate the assistance functions of full-body suits by focusing on EMG measures of the crural muscles, the center of mass positions, and the elevation angle of the chest in order to evaluate the assisting functions of a full-body suit when the subjects wearing the suit are in an upright position and changes occur in their posture. As a consequence, it was found that EMG measures of the tibialis anterior may reflect the assisting effects of the suit's elastic material around the ankle joints and that the center of gravity position and the elevation angle may reflect the posture correcting effect of the suit. In the future, we would like to verify this evaluation method by using elderly people and people with weak muscles as the test subjects.