Objective. To discuss the necessity that human mechanics and its physiological basis as applied to the research of human motion in many areas. Method. The motion performance of two aerospace [correction of areospace] pressure suit were studied. Human mechanics and its physiological basis was applied in the design of one suit only. Result. The result showed that good performance was obtained with the suit designed according to this principle which the stipulated actions couldn't be well performanced when wearing the suit not so designed. Conclusion. The research of the application of human mechanics and its physiological basis is necessary and it has better reality and is more scientific than applying biomechanics and robotics.