By using the method of constant stimuli, binocular-disparity based and motion-parallax based cylinders with various depths were produced in three-dimensional space as experimental stimuli. Observers were asked to walk in the three-dimensional space, and depth perception data at different viewing distances were obtained by using binocular-disparity cue, motion-parallax cue, and both binocular-disparity and motion-parallax cues separately. The experimental results show: at different viewing distances, binocular-disparity and motion-parallax cues have different influences on depth perception. In the far-distance viewing condition, the weight of motion parallax cue in depth perception is relatively larger than that in the near-distance viewing condition; in the near-distance viewing condition, when binocular-disparity and motion-parallax cues are combined, there is no promotive effect in depth perception and the effect of motion parallax cue is very small.