In　this　paper,　the　diffusion　entropy　technique　is　applied　to　investigate　the　scaling　behavior　of　stride　interval　fluctuations　of　human　gait.　The　scaling　behaviors　of　the　stride　interval　of　human　walking　at　norm,　slow,　and　fast　rate　are　similar;　with　the　scale-invariance　exponents　in　the　interval　[0.663,0.955],　of　which　the　mean　value　is　0.821　+/-　0.011.　Dynamical　analysis　of　these　stride　interval　fluctuations　reveals　a　self-similar　pattern:　fluctuation　at　one　time　scale　are　statistically　similar　to　those　at　multiple　other　time　scales,　at　least　over　hundreds　of　steps,　while　the　healthy　subjects　walk　at　their　norm　rate.　The　long-range　correlations　are　observed　during　the　spontaneous　walking　by　removal　of　the　trend　in　the　time　series　with　Fourier　filter.　These　findings　uncover　that　the　fractal　dynamics　of　stride　interval　fluctuation　of　human　gait　are　normally　intrinsic　to　the　locomotor　systems.　(c)　2006　Elsevier　B.V.　All　rights　reserved.