Abstract: Given the fact of the aging society across the world and the enlarging population with disability,fall is becoming a serious social problem.As the theoretical basis of fall prevention,the dynamic stability theory of human body has achieved an important improvement.Dynamic stability differs from static stability with the latter characterizing the relationship between the positions of center of mass(COM) of human body and its base of support.However,the former takes into consideration the factor of COM velocity besides the position;and describes the dynamic relationship between COM motion state(i.e.,the combination of position & velocity of COM of human) and dynamic stability region.Stability can be used to determine if the human body is in stable condition.Further,it can be employed to evaluate the degree of stability of human quantitatively.There are two contributing factors which cause falls:instability and weak weight support.Perturbation training in fall prevention can improve stability before and after slip,which represents the neurophysiology influences of feed-forward control and feedback control on dynamic stability of human body respectively.