The characteristics of the displacement velocity of center of pressure (COP) in the travel path were investigated when negotiating obstacles. Seven subjects (all female) were examined when negotiating obstacles of different heights at their self-selected pace. The COP velocities in the loading response phase were consistent between the 4 steps prior to obstacles. In the mid-stance phase, the COP velocities decreased as approaching toward obstacles. During the terminal stance phase and the pre-swing phase, the COP velocities of the second step prior to the obstacles had the greatest values than that of the other steps. It is found that when negotiating obstacles, the COP velocities of the 4 sub-stance phases of stance phase are influenced by the step, but not obstacle height for the young people while obstacle height is within 15% body height.