The invention discloses a three-dimensional hand-writing recognition system which allows the user to write characters freely in a three dimensional space in a non-contacting mode, without any kind ofphysical medium e.g. a notepad or a writing board, wherein the system input device tracks the userí»s hand-written input in the three dimensional space to produce the corresponding three-dimensional motion data, and to transmit the data to the system recognition apparatus wirelessly. In accordance with the method by the invention, the user can input characters without the limitation of screen, notepad or plane surface.